Western Australia Opposition Leader Troy Buswell last year sparked outrage among many ministers of parliament when he snapped the bra strap of a Labor staffer during a drunken episode in Parliament.
Western Australia Attorney-General Jim McGinty on Tuesday said the event showed parliamentary staff were not properly protected by the Equal Opportunity Act.
Staff members must have an employment connection to the person they are accusing of sexual harassment for it to apply.
This is difficult to establish in parliament because there is no direct employment relationship between ministers of parliament and staff.
But under the proposed changes, sexual advances, innuendo or other actions by any minister of parliament to staffers could be subject to a sexual harassment allegation.
McGinty said the new law would be based on South Australia's Equal Opportunity Act.
"I think the Buswell incident last year brought this into very sharp focus that we have a deficiency in the law,'' the attorney-general said.
"This law will make a special provision for members of parliament that we don't need to make an employment connection.
"All that needs to be done is if a member of parliament sexually harasses anyone else who has a connection with Parliament House then they will be able to be dealt with through the complaint procedure, whether it be by the Parliament or by the Equal Opportunity Commission or the State Administrative Tribunal.''
The penalty for sexual harassment under the Equal Opportunity Act is $40,000 compensation paid to the victim.