diff --git a/deb/reflist.go b/deb/reflist.go
index 008316ea..7da58773 100644
--- a/deb/reflist.go
+++ b/deb/reflist.go
@@ -84,6 +84,14 @@ func (l *PackageRefList) ForEach(handler func([]byte) error) error {
 	return err
 }
 
+// Has checks whether package is part of reflist
+func (l *PackageRefList) Has(p *Package) bool {
+	key := p.Key("")
+
+	i := sort.Search(len(l.Refs), func(j int) bool { return bytes.Compare(l.Refs[j], key) >= 0 })
+	return i < len(l.Refs) && bytes.Compare(l.Refs[i], key) == 0
+}
+
 // Substract returns all packages in l that are not in r
 func (l *PackageRefList) Substract(r *PackageRefList) *PackageRefList {
 	result := &PackageRefList{Refs: make([][]byte, 0, 128)}
diff --git a/deb/reflist_test.go b/deb/reflist_test.go
index 4a0dabb9..c1fdb4ec 100644
--- a/deb/reflist_test.go
+++ b/deb/reflist_test.go
@@ -128,6 +128,19 @@ func (s *PackageRefListSuite) TestPackageRefListForeach(c *C) {
 	c.Check(err, Equals, e)
 }
 
+func (s *PackageRefListSuite) TestHas(c *C) {
+	s.list.Add(s.p1)
+	s.list.Add(s.p3)
+	s.list.Add(s.p5)
+	reflist := NewPackageRefListFromPackageList(s.list)
+
+	c.Check(reflist.Has(s.p1), Equals, true)
+	c.Check(reflist.Has(s.p3), Equals, true)
+	c.Check(reflist.Has(s.p5), Equals, true)
+	c.Check(reflist.Has(s.p2), Equals, true)
+	c.Check(reflist.Has(s.p6), Equals, false)
+}
+
 func (s *PackageRefListSuite) TestSubstract(c *C) {
 	r1 := []byte("r1")
 	r2 := []byte("r2")