Local Government Minister Tony Simpson has resigned from the state government's cabinet, saying he no longer fully supports Premier Colin Barnett.

The former minister issued a statement saying that the party's leadership issue now needs to be brought to a head.

"I have taken this step reluctantly and with a heavy heart, but have done so because I no longer have confidence in the direction and leadership being offered by the Premier and hence cannot say that he has my full support.

"I hope the issue of leadership with the Parliamentary Liberal Party will come to a head. In any case, relinquishing my Ministerial duties will give me more time to devote to my electorate and the task of retaining the seat of Darling Range.