Opposition immigration spokesman Scott Morrison has moved to justify his calls for neighbours and police to be alerted when asylum seekers on bridging visas are placed in the community.

Mr Morrison made the comments after a Sri Lankan asylum seeker living in Sydney on a bridging visa was charged with the indecent assault of a 20-year-old university student.

Opposition Leader Tony Abbott says he supports Mr Morrison's stance, but Liberal backbencher Russell Broadbent says it amounts to vilification.

Government MPs described the comments as unpalatable and unacceptable.

Mr Morrison told the ABC's Insiders program this morning that he was not suggesting a blanket approach for all asylum seekers on bridging visas - only the large groups who are relocated together.

"I'm referring to the arranged accommodation by the service providers," he said.

"That's what I'm referring to, that's what my press release referred to.

"This is where the Government themselves through their service providers are taking out the lease."

Mr Morrison says because asylum seekers on bridging visas have not gone through rigorous identity and security checks at that stage of their processing, his concerns are justified.

"Their identity hasn't been fully tested, nor has ASIO done full security checks on anyone who has been released," he said.

"There is a light touch based on who people say they are but as we know with more than 90 per cent of people turning up without documentation, I think these are reasonable commonsense safeguards."

Manus visit

Mr Morrison spoke from Papua New Guinea where he was visiting the Manus Island detention centre.

He said he was "very puzzled" as to why single adult males were being kept alongside a group of mothers.

"A group of mothers in particular... expressed to me very serious concerns about the behaviour of the single adult males," he told Insiders.

"I'm talking about protest activity, fighting and loud noises and these sorts of things, I'm not suggesting anything else.

"I don't think it is as appropriate and it's certainly something I'd be taking a look at.

"I think the Government would need to explain why they're finding the need to do just that with this facility.

"I mean, it's not done anywhere else in the detention network."