A downhole packer assembly includes a body part, an expandable tubular packer element surrounding the body part, and a first end and a second end of the expandable tubular packer element are fixedly connected with the body part, providing an expandable space fillable with liquid during expansion, and a metal sleeve surrounding the expandable tubular packer element. A restriction unit has an axially movable part movable between a first axial position in which the axially movable part at least partly overlaps the expandable tubular packer element and a second axial position in which the axially movable part has been axially displaced in relation to the body part away from the expandable tubular packer element.