Western Australia's Deputy Premier Liza Harvey insists she will never be involved in a spill motion against Colin Barnett, or tell him it is time to go, amid continued Liberal leadership tensions.

Mrs Harvey insisted the Premier, who has been leader since 2008, was the best person for the job and would lead the Liberals to the election next March.

Mr Barnett's decision not to sack Dean Nalder has renewed leadership tensions, with several key figures within the party frustrated the Transport Minister was not dumped from Cabinet over his knowledge of private polling commissioned by prominent business figures.

Those events are understood to have triggered fresh discussions within the party over Mr Barnett's future and whether a switch needs to be made to Mrs Harvey before the election.

But Mrs Harvey said she was still firmly behind the Premier and was not pushing for a leadership change.

"I will never be party to a spill motion to the Premier. He has my unequivocal support and I am 100 per cent behind him," she said.

"The Premier is the leader of the party. He will take us to the election and I believe he is the best person to take us through.

"I thought that was very interesting when I heard there was a push to have me installed as an alternative leader, because I had thought someone might want to have that conversation with me if that was the case.

"I will not be tapping the Premier on the shoulder."

Mrs Harvey defended Mr Barnett's decisions surrounding Mr Nalder, who is on leave for a week following the polling scandal.

"I'm not privy to all the conversation that occurred between Mr Nalder and the Premier but I have confidence in the Premier's decision making," she said.

Meanwhile, Mrs Harvey and Attorney-General Michael Mischin have announced nearly $5 million in land purchases for a proposed Armadale justice complex.

The proposal would see a new courthouse and police station built on the land, with the Government allocating $1.8 million for planning this financial year.