diff --git a/v2/object/convert.go b/v2/object/convert.go
index 84ae218..88b0e0e 100644
--- a/v2/object/convert.go
+++ b/v2/object/convert.go
@@ -1258,14 +1258,9 @@ func SearchResponseBodyToGRPCMessage(r *SearchResponseBody) *object.SearchRespon
 
 	m := new(object.SearchResponse_Body)
 
-	ids := r.GetIDList()
-	idMsg := make([]*refsGRPC.ObjectID, 0, len(ids))
-
-	for i := range ids {
-		idMsg = append(idMsg, refs.ObjectIDToGRPCMessage(ids[i]))
-	}
-
-	m.SetIdList(idMsg)
+	m.SetIdList(
+		refs.ObjectIDListToGRPCMessage(r.GetIDList()),
+	)
 
 	return m
 }
@@ -1277,14 +1272,9 @@ func SearchResponseBodyFromGRPCMessage(m *object.SearchResponse_Body) *SearchRes
 
 	r := new(SearchResponseBody)
 
-	idMsg := m.GetIdList()
-	ids := make([]*refs.ObjectID, 0, len(idMsg))
-
-	for i := range idMsg {
-		ids = append(ids, refs.ObjectIDFromGRPCMessage(idMsg[i]))
-	}
-
-	r.SetIDList(ids)
+	r.SetIDList(
+		refs.ObjectIDListFromGRPCMessage(m.GetIdList()),
+	)
 
 	return r
 }
diff --git a/v2/object/marshal.go b/v2/object/marshal.go
index c321ed3..59ac0ad 100644
--- a/v2/object/marshal.go
+++ b/v2/object/marshal.go
@@ -3,6 +3,7 @@ package object
 import (
 	"github.com/nspcc-dev/neofs-api-go/util/proto"
 	object "github.com/nspcc-dev/neofs-api-go/v2/object/grpc"
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	goproto "google.golang.org/protobuf/proto"
 )
 
@@ -295,15 +296,13 @@ func (h *SplitHeader) StableMarshal(buf []byte) ([]byte, error) {
 
 	offset += n
 
-	for i := range h.children {
-		n, err = proto.NestedStructureMarshal(splitHdrChildrenField, buf[offset:], h.children[i])
-		if err != nil {
-			return nil, err
-		}
-
-		offset += n
+	n, err = refs.ObjectIDNestedListMarshal(splitHdrChildrenField, buf[offset:], h.children)
+	if err != nil {
+		return nil, err
 	}
 
+	offset += n
+
 	_, err = proto.BytesMarshal(splitHdrSplitIDField, buf[offset:], h.splitID)
 	if err != nil {
 		return nil, err
@@ -321,11 +320,7 @@ func (h *SplitHeader) StableSize() (size int) {
 	size += proto.NestedStructureSize(splitHdrPreviousField, h.prev)
 	size += proto.NestedStructureSize(splitHdrParentSignatureField, h.parSig)
 	size += proto.NestedStructureSize(splitHdrParentHeaderField, h.parHdr)
-
-	for i := range h.children {
-		size += proto.NestedStructureSize(splitHdrChildrenField, h.children[i])
-	}
-
+	size += refs.ObjectIDNestedListSize(splitHdrChildrenField, h.children)
 	size += proto.BytesSize(splitHdrSplitIDField, h.splitID)
 
 	return size
@@ -1227,17 +1222,13 @@ func (r *SearchResponseBody) StableMarshal(buf []byte) ([]byte, error) {
 	}
 
 	var (
-		offset, n int
-		err       error
+		offset int
+		err    error
 	)
 
-	for i := range r.idList {
-		n, err = proto.NestedStructureMarshal(searchRespBodyObjectIDsField, buf[offset:], r.idList[i])
-		if err != nil {
-			return nil, err
-		}
-
-		offset += n
+	_, err = refs.ObjectIDNestedListMarshal(searchRespBodyObjectIDsField, buf[offset:], r.idList)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -1248,9 +1239,7 @@ func (r *SearchResponseBody) StableSize() (size int) {
 		return 0
 	}
 
-	for i := range r.idList {
-		size += proto.NestedStructureSize(searchRespBodyObjectIDsField, r.idList[i])
-	}
+	size += refs.ObjectIDNestedListSize(searchRespBodyObjectIDsField, r.idList)
 
 	return size
 }
diff --git a/v2/refs/convert.go b/v2/refs/convert.go
index 00971be..673fbf0 100644
--- a/v2/refs/convert.go
+++ b/v2/refs/convert.go
@@ -76,6 +76,34 @@ func ObjectIDFromGRPCMessage(m *refs.ObjectID) *ObjectID {
 	return o
 }
 
+func ObjectIDListToGRPCMessage(ids []*ObjectID) []*refs.ObjectID {
+	if ids == nil {
+		return nil
+	}
+
+	idsV2 := make([]*refs.ObjectID, 0, len(ids))
+
+	for i := range ids {
+		idsV2 = append(idsV2, ObjectIDToGRPCMessage(ids[i]))
+	}
+
+	return idsV2
+}
+
+func ObjectIDListFromGRPCMessage(idsV2 []*refs.ObjectID) []*ObjectID {
+	if idsV2 == nil {
+		return nil
+	}
+
+	ids := make([]*ObjectID, 0, len(idsV2))
+
+	for i := range idsV2 {
+		ids = append(ids, ObjectIDFromGRPCMessage(idsV2[i]))
+	}
+
+	return ids
+}
+
 func AddressToGRPCMessage(a *Address) *refs.Address {
 	if a == nil {
 		return nil
diff --git a/v2/refs/marshal.go b/v2/refs/marshal.go
index 3c3ef1e..28b4d4e 100644
--- a/v2/refs/marshal.go
+++ b/v2/refs/marshal.go
@@ -115,6 +115,16 @@ func (o *ObjectID) StableMarshal(buf []byte) ([]byte, error) {
 	return buf, nil
 }
 
+// ObjectIDNestedListSize returns byte length of nested
+// repeated ObjectID field with fNum number.
+func ObjectIDNestedListSize(fNum int64, ids []*ObjectID) (sz int) {
+	for i := range ids {
+		sz += proto.NestedStructureSize(fNum, ids[i])
+	}
+
+	return
+}
+
 func (o *ObjectID) StableSize() int {
 	if o == nil {
 		return 0
@@ -123,6 +133,23 @@ func (o *ObjectID) StableSize() int {
 	return proto.BytesSize(objectIDValField, o.val)
 }
 
+// ObjectIDNestedListMarshal writes protobuf repeated ObjectID field
+// with fNum number to buf.
+func ObjectIDNestedListMarshal(fNum int64, buf []byte, ids []*ObjectID) (off int, err error) {
+	for i := range ids {
+		var n int
+
+		n, err = proto.NestedStructureMarshal(fNum, buf[off:], ids[i])
+		if err != nil {
+			return
+		}
+
+		off += n
+	}
+
+	return
+}
+
 func (o *ObjectID) Unmarshal(data []byte) error {
 	m := new(refs.ObjectID)
 	if err := goproto.Unmarshal(data, m); err != nil {
diff --git a/v2/storagegroup/convert.go b/v2/storagegroup/convert.go
index 6712619..e78312c 100644
--- a/v2/storagegroup/convert.go
+++ b/v2/storagegroup/convert.go
@@ -2,7 +2,6 @@ package storagegroup
 
 import (
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
-	refsGRPC "github.com/nspcc-dev/neofs-api-go/v2/refs/grpc"
 	sg "github.com/nspcc-dev/neofs-api-go/v2/storagegroup/grpc"
 )
 
@@ -20,14 +19,9 @@ func StorageGroupToGRPCMessage(s *StorageGroup) *sg.StorageGroup {
 	)
 	m.SetExpirationEpoch(s.GetExpirationEpoch())
 
-	members := s.GetMembers()
-	memberMsg := make([]*refsGRPC.ObjectID, 0, len(members))
-
-	for i := range members {
-		memberMsg = append(memberMsg, refs.ObjectIDToGRPCMessage(members[i]))
-	}
-
-	m.SetMembers(memberMsg)
+	m.SetMembers(
+		refs.ObjectIDListToGRPCMessage(s.GetMembers()),
+	)
 
 	return m
 }
@@ -46,14 +40,9 @@ func StorageGroupFromGRPCMessage(m *sg.StorageGroup) *StorageGroup {
 	)
 	s.SetExpirationEpoch(m.GetExpirationEpoch())
 
-	memberMsg := m.GetMembers()
-	members := make([]*refs.ObjectID, 0, len(memberMsg))
-
-	for i := range memberMsg {
-		members = append(members, refs.ObjectIDFromGRPCMessage(memberMsg[i]))
-	}
-
-	s.SetMembers(members)
+	s.SetMembers(
+		refs.ObjectIDListFromGRPCMessage(m.GetMembers()),
+	)
 
 	return s
 }
diff --git a/v2/storagegroup/marshal.go b/v2/storagegroup/marshal.go
index bfcb896..c7d4e75 100644
--- a/v2/storagegroup/marshal.go
+++ b/v2/storagegroup/marshal.go
@@ -2,6 +2,7 @@ package storagegroup
 
 import (
 	"github.com/nspcc-dev/neofs-api-go/util/proto"
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	storagegroup "github.com/nspcc-dev/neofs-api-go/v2/storagegroup/grpc"
 	goproto "google.golang.org/protobuf/proto"
 )
@@ -50,13 +51,9 @@ func (s *StorageGroup) StableMarshal(buf []byte) ([]byte, error) {
 
 	offset += n
 
-	for i := range s.members {
-		n, err = proto.NestedStructureMarshal(objectIDsField, buf[offset:], s.members[i])
-		if err != nil {
-			return nil, err
-		}
-
-		offset += n
+	n, err = refs.ObjectIDNestedListMarshal(objectIDsField, buf[offset:], s.members)
+	if err != nil {
+		return nil, err
 	}
 
 	return buf, nil
@@ -71,10 +68,7 @@ func (s *StorageGroup) StableSize() (size int) {
 	size += proto.UInt64Size(sizeField, s.size)
 	size += proto.NestedStructureSize(hashField, s.hash)
 	size += proto.UInt64Size(expirationField, s.exp)
-
-	for i := range s.members {
-		size += proto.NestedStructureSize(objectIDsField, s.members[i])
-	}
+	size += refs.ObjectIDNestedListSize(objectIDsField, s.members)
 
 	return size
 }