diff --git a/internal/error.go b/internal/error.go
deleted file mode 100644
index 537c02ca..00000000
--- a/internal/error.go
+++ /dev/null
@@ -1,9 +0,0 @@
-package internal
-
-// Error is constant type error.
-type Error string
-
-// Error implementation of error interface.
-func (e Error) Error() string {
-	return string(e)
-}
diff --git a/pkg/container/id.go b/pkg/container/id.go
index 659828fd..bdf3f8ea 100644
--- a/pkg/container/id.go
+++ b/pkg/container/id.go
@@ -5,7 +5,6 @@ import (
 	"crypto/sha256"
 
 	"github.com/mr-tron/base58"
-	"github.com/nspcc-dev/neofs-api-go/internal"
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	"github.com/pkg/errors"
 )
@@ -13,9 +12,7 @@ import (
 // ID represents v2-compatible container identifier.
 type ID refs.ContainerID
 
-// ErrBadID should be returned when bytes slice isn't Container.ID size (sha256.Size).
-// Notice: if byte slice changed, please, replace error message.
-const ErrBadID = internal.Error("object.ID should be 32 bytes length")
+var errInvalidIDString = errors.New("incorrect format of the string container ID")
 
 // NewIDFromV2 wraps v2 ContainerID message to ID.
 func NewIDFromV2(idV2 *refs.ContainerID) *ID {
@@ -53,7 +50,7 @@ func (id *ID) Parse(s string) error {
 	if err != nil {
 		return errors.Wrap(err, "could not parse container.ID from string")
 	} else if len(data) != sha256.Size {
-		return ErrBadID
+		return errInvalidIDString
 	}
 
 	(*refs.ContainerID)(id).SetValue(data)
diff --git a/pkg/container/id_test.go b/pkg/container/id_test.go
index 33469751..346a1873 100644
--- a/pkg/container/id_test.go
+++ b/pkg/container/id_test.go
@@ -70,7 +70,7 @@ func TestID_Parse(t *testing.T) {
 				str := base58.Encode(cs)
 				cid := NewID()
 
-				require.EqualError(t, cid.Parse(str), ErrBadID.Error())
+				require.Error(t, cid.Parse(str))
 			})
 		}
 	})
diff --git a/pkg/object/address.go b/pkg/object/address.go
index 7f2bfe77..a2281a73 100644
--- a/pkg/object/address.go
+++ b/pkg/object/address.go
@@ -1,9 +1,9 @@
 package object
 
 import (
+	"errors"
 	"strings"
 
-	"github.com/nspcc-dev/neofs-api-go/internal"
 	"github.com/nspcc-dev/neofs-api-go/pkg/container"
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 )
@@ -11,9 +11,7 @@ import (
 // Address represents v2-compatible object address.
 type Address refs.Address
 
-// ErrBadAddress returns when string representation doesn't
-// contains Container.ID and Object.ID separated by `/`.
-const ErrBadAddress = internal.Error("address should contains container.ID and object.ID separated with `/`")
+var errInvalidAddressString = errors.New("incorrect format of the string object address")
 
 const (
 	addressParts     = 2
@@ -71,7 +69,7 @@ func (a *Address) Parse(s string) error {
 	)
 
 	if len(parts) != addressParts {
-		return ErrBadAddress
+		return errInvalidAddressString
 	} else if err = cid.Parse(parts[0]); err != nil {
 		return err
 	} else if err = oid.Parse(parts[1]); err != nil {
diff --git a/pkg/object/address_test.go b/pkg/object/address_test.go
index d0316705..e17fc4d6 100644
--- a/pkg/object/address_test.go
+++ b/pkg/object/address_test.go
@@ -47,17 +47,17 @@ func TestAddress_Parse(t *testing.T) {
 
 	t.Run("should fail for bad address", func(t *testing.T) {
 		s := strings.Join([]string{cid.String()}, addressSeparator)
-		require.EqualError(t, NewAddress().Parse(s), ErrBadAddress.Error())
+		require.EqualError(t, NewAddress().Parse(s), errInvalidAddressString.Error())
 	})
 
 	t.Run("should fail on container.ID", func(t *testing.T) {
 		s := strings.Join([]string{"1", "2"}, addressSeparator)
-		require.EqualError(t, NewAddress().Parse(s), container.ErrBadID.Error())
+		require.Error(t, NewAddress().Parse(s))
 	})
 
 	t.Run("should fail on object.ID", func(t *testing.T) {
 		s := strings.Join([]string{cid.String(), "2"}, addressSeparator)
-		require.EqualError(t, NewAddress().Parse(s), ErrBadID.Error())
+		require.Error(t, NewAddress().Parse(s))
 	})
 }
 
diff --git a/pkg/object/id.go b/pkg/object/id.go
index c62451d0..813793dd 100644
--- a/pkg/object/id.go
+++ b/pkg/object/id.go
@@ -5,7 +5,6 @@ import (
 	"crypto/sha256"
 
 	"github.com/mr-tron/base58"
-	"github.com/nspcc-dev/neofs-api-go/internal"
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	"github.com/pkg/errors"
 )
@@ -13,9 +12,7 @@ import (
 // ID represents v2-compatible object identifier.
 type ID refs.ObjectID
 
-// ErrBadID should be returned when bytes slice hasn't sha256.Size
-// Notice: if byte slice changed, please, replace error message.
-const ErrBadID = internal.Error("object.ID should be 32 bytes length")
+var errInvalidIDString = errors.New("incorrect format of the string object ID")
 
 // NewIDFromV2 wraps v2 ObjectID message to ID.
 func NewIDFromV2(idV2 *refs.ObjectID) *ID {
@@ -53,7 +50,7 @@ func (id *ID) Parse(s string) error {
 	if err != nil {
 		return errors.Wrap(err, "could not parse object.ID from string")
 	} else if len(data) != sha256.Size {
-		return ErrBadID
+		return errInvalidIDString
 	}
 
 	(*refs.ObjectID)(id).SetValue(data)
diff --git a/pkg/object/id_test.go b/pkg/object/id_test.go
index 14ab6c67..a11e80b1 100644
--- a/pkg/object/id_test.go
+++ b/pkg/object/id_test.go
@@ -63,7 +63,7 @@ func TestID_Parse(t *testing.T) {
 				str := base58.Encode(cs)
 				oid := NewID()
 
-				require.EqualError(t, oid.Parse(str), ErrBadID.Error())
+				require.Error(t, oid.Parse(str))
 			})
 		}
 	})
diff --git a/pkg/owner/id.go b/pkg/owner/id.go
index 49acb2cc..e6a240d6 100644
--- a/pkg/owner/id.go
+++ b/pkg/owner/id.go
@@ -3,7 +3,6 @@ package owner
 import (
 	"github.com/mr-tron/base58"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
-	"github.com/nspcc-dev/neofs-api-go/internal"
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	"github.com/pkg/errors"
 )
@@ -11,9 +10,7 @@ import (
 // ID represents v2-compatible owner identifier.
 type ID refs.OwnerID
 
-// ErrBadID should be returned when bytes slice isn't Owner.ID size (NEO3WalletSize).
-// Notice: if byte slice changed, please, replace error message.
-const ErrBadID = internal.Error("owner.ID should be 25 bytes length")
+var errInvalidIDString = errors.New("incorrect format of the string owner ID")
 
 // NewIDFromV2 wraps v2 OwnerID message to ID.
 func NewIDFromV2(idV2 *refs.OwnerID) *ID {
@@ -64,7 +61,7 @@ func (id *ID) Parse(s string) error {
 	if err != nil {
 		return errors.Wrap(err, "could not parse owner.ID from string")
 	} else if len(data) != NEO3WalletSize {
-		return ErrBadID
+		return errInvalidIDString
 	}
 
 	(*refs.OwnerID)(id).SetValue(data)
diff --git a/pkg/owner/id_test.go b/pkg/owner/id_test.go
index 8d867df4..49816bf8 100644
--- a/pkg/owner/id_test.go
+++ b/pkg/owner/id_test.go
@@ -64,7 +64,7 @@ func TestID_Parse(t *testing.T) {
 				str := base58.Encode(cs)
 				cid := NewID()
 
-				require.EqualError(t, cid.Parse(str), ErrBadID.Error())
+				require.Error(t, cid.Parse(str))
 			})
 		}
 	})