Gloucestershire line up Noffke
Noffke will replace Gul if, as expected, he is called up to Pakistan's World Cup squad.
Gloucestershire head coach Mark Alleyne said: "I am very excited at gaining the services of Ashley at the start of the season. He is a top performer and the timing couldn't have been better as Ashley looks to re-launch his bid for a place in the Australian side. I look forward to working closely with him."
Noffke, who plays for Queensland, has previously had spells at Middlesex and Durham and has taken 256 first-class wickets in 79 matches. He came to attention when he was selected for the Ashes tour in 2001 but has since failed to convince the Australian selectors.