THE push for gay marriage is threatening to ignite open warfare among WA Liberals, with conservatives preparing their own Bill seeking sweeping protection for “conscientious objectors” opposed to change.

A group of conservative MPs including WA Liberals Ian Goodenough and Andrew Hastie are preparing a Bill to change the Marriage Act in the event of a Yes vote.

It will include sweeping provisions to protect religious freedoms and those who oppose same-sex marriage “beyond the ceremony”.

The group also includes conservative senators Zed Seselja, Cory Bernardi and Eric Abetz.

Camera Icon Andrew Hastie. Credit: PerthNow, Richard Polden

Mr Goodenough saidthe group had begun working on the legislation amid concern that the safeguards proposed by WA Liberal senator Dean Smith did not go far enough.

“It’s to ensure that because we are making such a big change to a fundamental institution in our society we need to think about the broader implications — it goes beyond the wedding ceremony,” Mr Goodenough said.

He also suggested Parliament could face a furious debate about which Bill to support in the event of a Yes result, with several Bills potentially put forward for a vote. “It could get quite messy if several members move Bills as to which one gets the carriage through Parliament,” Mr Goodenough said, suggesting it may be “ambitious” to have legislation passed by Christmas.

Mr Hastie said he backed the view of former prime minister John Howard, who has called on the Federal Government to outline how parental rights and freedom of speech and religion will be protected in a same-sex marriage Bill.

Camera Icon Federal MP Ian Goodenough. Credit: PerthNow, Matthew Tompsett

“Of course people on the No side of the debate are discussing what protections would look like if a Yes vote is returned in November,” Mr Hastie said.

Prime Minister Malcolm Turnbull has said that if a Yes vote prevails, Parliament will debate the legislation and any safeguards needed to protect religious freedoms.

Senator Smith said he did not think that MPs would want to see any watering down of anti-discrimination laws, but welcomed the discussion of other Bills.