Corrective Services Minister Murray Cowper is being investigated for alleged illegal land clearing at a holiday shack community, prompting calls for him to be sacked.
The Department of Environment and Conservation confirmed Mr Cowper was being investigated under the Environmental Protection Act.
Mr Cowper, who is also Minister for Training and Workforce Development, said he used a small earthmover to clear sand piled up next to a shack on Wedge Island.
Mr Cowper said he did not know that clearing the sand was not allowed until a DEC officer told him, and he understood that was based on new information.
But the DEC said the land clearing laws had not changed.
Opposition treasury spokesman Ben Wyatt called for Mr Cowper to be sacked.
But Premier Colin Barnett said he was not jumping to conclusions, and was not aware of the matter until this morning.
Mr Wyatt said it was not tenable for a minister to be under investigation.
“I don’t think anybody would accept that,” he said.
Mr Wyatt also said Mr Barnett prided his party on high standards of accountability.
The Liberal leader has frequently reminded voters during the current election campaign that five ministers under the previous Labor government were forced to resign or were sacked after becoming embroiled in Corruption and Crime Commission inquiries.
The Wedge Island community began as a haven for surfers but has become popular with other holidaymakers.
The shacks themselves would normally be considered illegal as they are on a declared nature reserve, but have been tolerated amid a campaign to “Save Wedge Island”.
The State Government is keeping the shacks on rolling leases until a plan for better management of the area can be devised.