West Australian fast bowlers Brad Knowles and Mark Cameron have announced their retirements from interstate cricket, the pair succumbing to injuries.

Knowles, 30, was a former Victorian squad member who moved west in the 2008-09 season.

He took 30 wickets in the Sheffield Shield the following season and nine scalps in both the domestic one-day and T20 competitions.

But a serious knee injury suffered prior to the start of the 2010-11 season sidelined him for the summer and he has been unable to play for the Warriors since.

Cameron, 31, made his debut for NSW in 2002-03 but was restricted to 16 first class, 12 one-day and six Twenty20 matches for the Blues in nine seasons.

He shifted to Western Australia in the 2011 winter but was unable to play a match due to persistent back injuries.