An access valve (2) for a laparoscopic device or a intraluminal deployment device has a cylindrical diaphragm (8) with a longitudinal aperture (3), a flexible member (14) is passed circumferentially around the cylindrical diaphragm and an extension arrangement to pull the flexible member radially and/or tangentially to constrict the diaphragm to at least partially close off the longitudinal aperture. A rotary actuator may be used (12).