Liberal rebel Andrew Hastie has quit the shadow cabinet, declaring he could not serve there because Sussan Ley had told him he would have no role in formulating the opposition’s immigration policy.

Hastie rang Ley with his decision early Friday. This follows his increasing public frustration, expressed via social media posts, including about immigration.

Hastie’s quitting is another blow for Ley, especially as it comes ahead of a parliamentary sitting week. It follows her recently forcing Senator Jacinta Nampijinpa Price off the front bench after Price refused to endorse Ley’s leadership.

Hastie has made it clear he has leadership ambitions but Ley is considered safe in her position for the time being. But he is making it clear that he will speak out on issues, which will add to Ley’s problem of disunity within Liberal ranks.

The tension with Hastie came to a head after Ley sent her frontbenchers letters outlining their responsibilities in detail.

Hastie said in a Friday email to supporters: “during the week, I received a letter from the Leader outlining her expectations of me as the Shadow Minister for Home Affairs.

"In the letter, she made it clear that I would not be involved in leading or developing our policy or strategy on immigration.

"In my judgement, that would make it impossible for me to comment on the topic, despite it being central to the Home Affairs portfolio.

"I could not see how I could continue as the Shadow Home Affairs Minister and remain silent on immigration policy.

"One of the things the Leader rightly emphasised was the longstanding convention of Shadow Cabinet solidarity. This rule applies to those who sit at the big table.

"In my case, our position on immigration would be binding, even though I’d have no role in policy that is central to the Home Affairs portfolio.”

Hastie said looking to the future he wanted to be able to “speak freely in the contest of ideas.”

In a statement Ley said the letters were developed with extensive consultation with shadow ministers.

She had had more than 50 one-on-one conversations with her team, including Hastie.

“These letters provide clear direction and tasking to shadow ministers beyond the conventional mirroring of government portfolios, putting the Coalition on a proactive policy path.

"They set out key performance indicators, general expectations and shared policy priorities that I have personally agreed with each Shadow Minister.

"They enable the Coalition to develop a serious and credible policy platform to take to the next election, where we will draw a clear contrast with Labor,” Ley said.

Ley said with news breaking on Friday that ISIS brides had secretly returned to Australia, this was a very important time for the Opposition to strongly scrutinise the government in the home affairs area.

The Guardian on Friday reported that two women and four children have returned to Australia from a Syrian detention camp, without assistance from the Australian government.

“It is disappointing that this crucial Opposition portfolio has been left vacant today,” Ley said.

Ley has appointed Finance Spokesman James Paterson to temporarily act in the home affairs portfolio. Paterson was previously spokesman for home affairs.