In an address to the National Press Club on Wednesday, Liberal housing spokesman Andrew Bragg said his party would reduce net annual migration to 180,000.
Treasury modelling published in the May budget expected net overseas migration to fall from 301,000 to 225,000 by the end of this decade.
That would mean a dramatic cut to international students and working holiday visas, which was quickly ruled out by Nationals leader Matt Canavan, given farmers' reliance on migrant workers.
Angus Taylor said he had spoken with Senator Bragg since his speech and confirmed his suggestions were not official Liberal policy.
"Andrew expressed some of his personal views yesterday," he told reporters on Thursday.
"I've made clear to him that his job is to express ... the views of the coalition and the senior team of which he is a member when it comes to immigration policy."
In a blistering spray at his party, Senator Bragg used the speech to say the Liberals had contributed to Australia's economic malaise and the demise of the two-party system by failing to develop enough alternative policies and to take political risk for two decades.
He freelanced on other topics outside his remit, from the NDIS to multinational tax, before veering back to his housing portfolio.
Senator Bragg said the speech articulated Australia's housing crisis and migration was tied to that.
The main focus of the address was to promote a Senate report he chaired, which recommended slashing the National Construction Code from more than 2000 pages to a 90-page document of basic standards to make it cheaper and faster to build new homes.
"But I don't think you can disconnect the housing malaise from the nation's economic malaise," he told reporters on Thursday.
"Those broader points, of course, are just facts that the country is going bankrupt under this government."
Senator Bragg targeted "gold-plated" energy efficiency requirements, saying it was better for people to shiver in colder homes than not have a roof over their heads due to the chronic housing shortage.
Maiy Azize, spokeswoman for homelessness peak body Everybody's Home, said accessibility and energy efficiency were not luxuries.
"We have a housing crisis because people cannot afford a home," she said.
"Building more poor-quality homes does nothing to fix that crisis - it simply gives developers another way to profit from it."
Other coalition members, several of whom spoke to media on the condition of anonymity, also refused to back Senator Bragg's migration proposal.
