The WA Liberal candidate for the federal seat of Tangney, Mark Wales, has announced he will no longer contest the must-win seat.

Mr Wales won pre-selection for the seat last month with a clear majority.

But in a statement, the former SAS soldier and reality TV star said a close family member had recently suffered a "serious medical episode" and was in intensive care in Melbourne.

"When I spoke to Liberal Party members in Tangney during my preselection in April, I assured them that I share their fundamental values. Specifically, I said I was 'all in' for family," Mr Wales said.

"My family means everything to me – so my first priority is to be with them and provide all the support they need during this incredibly difficult time.

"This means I am not able to devote all my time and energy to being on the ground and campaigning locally in Tangney."

He said by stepping aside now, he would give the Liberal Party more time to pre-select a candidate for the seat.

The blue-ribbon seat was snatched from the Liberals at the last election by Labor's dolphin trainer-turned police officer Sam Lim, who secured an 11.9 per cent swing to hold the seat on a 2.4 per cent margin.

Mr Wales had won pre-selection over five other candidates, with two – Sean Ayres and Howard Ong – considered frontrunners at the time.

The party's State Council will hold a special meeting later this week to decide on the process of replacing him.

It's understood many of the candidates who contested pre-selection are still weighing up whether they would put their hands up again.

Mr Wales has written a book, set to be released later this year, which depicts a civil war in Australia following an invasion by Chinese forces.

At the time he was pre-selected, he denied the book would be controversial, saying the invasion was a "minor part of the story".

But the president of WA's Chung Wah Association, Ting Chen, believed Mr Wales' pre-selection showed the party was "ignorant of how the voters of Tangney think about a candidate who fantasised a war with our largest trading partner".

"Our community wants peace, more trade, not war," he said.

More than 16 per cent of residents in the seat identify as Chinese.