Attorney-General Christian Porter referred allegations made about government officials giving special treatment to Crown Casino to the Australian Commission for Law Enforcement Integrity on Tuesday, attempting to head off calls for a parliamentary inquiry into the claims.

Labor supported the referral and helped the government vote down the parliamentary inquiry.

The united position from the major parties ignited unity among crossbenchers in the call for a beefed-up national integrity commission, with more powers than those proposed by the government.

Seven crossbenchers appeared with former Victorian Supreme Court judge David Harper and the Australia Institute's Ben Oquist on Wednesday saying the allegations against MPs regarding Crown, and subsequent narrow investigation by the law enforcement watchdog, show the system isn't working.

The law enforcement integrity commission is limited to investigating officials from the Australian Federal Police, the Department of Home Affairs, Australian Border Force and a handful of other agencies, and can't investigate politicians.

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Under the Commonwealth Integrity Commission proposed by the government, the existing watchdog would be folded into the new body, but its coercive powers wouldn't extend across the full public service.

ACLEI also came under harsh criticism from the Australian National Audit Office last year, with the report finding there was no way to know if the watchdog was running efficiently, and that it wasn't increasing the number of cases it investigated and finalised.

Centre Alliance MP Rebekha Sharkie said this week's revelations and the government's reaction showed why a future Commonwealth Integrity Commission needed more powers and a wider remit.

Ms Sharkie said the government hadn't set aside enough funding for a national integrity commission.

Mr Harper said while ACLEI would do a good job of an investigation, it was too limited in what it could look at.

"I accept that ACLEI would do the best job it possibly can with the reference it's got. Assuming that it accepts that reference, it doesn't have to - it may decline to do anything," he said.

"But if it does accept the reference, it won't be able to examine the part, if any, that has been played by members of parliament in the Crown saga.

"And that, of course, is a real problem when you're investigating allegations that take in the activities of MPs."

Senator Jacqui Lambie and independent MP Helen Haines said a powerful integrity commission was needed to counter low levels of trust from the public in government.

"Throughout the election campaign I heard a loss of trust in our federal government, a loss of trust that in some places around the world can lead to populism," Ms Haines said.

"If we don't have a federal integrity commission, one with teeth, then we may as well not have one at all because this commission must be trusted by the people of Australia."

Independent Andrew Wilkie and Senator Lambie encouraged whistleblowers to come to the crossbenchers, who could tell their stories under parliamentary privilege.

"If you've got documents you want to produce to us, and you don't want to be named, I tell you what - we have no fear in standing up in the chamber and calling them out for what is going on here," Senator Lambie said.

Senator Lambie said she wanted a commission "with more teeth than Jaws," and would consider not voting for government bills if requests over the integrity commission were ignored.

The government started consultation on its proposed Commonwealth Integrity Commission in December, with submissions closing in February, but there hasn't been further announcements.