Coalition MPs have indicated they will push for a "full blown" parliamentary inquiry into the controversial Safe Schools anti-bullying program, rejecting a Government-commissioned review as a "joke".

Key points: Coalition MPs reject Government review into Safe Schools program

Coalition MPs reject Government review into Safe Schools program George Christensen will be writing to the PM to express his concerns

George Christensen will be writing to the PM to express his concerns Cory Bernardi said the review did not examine all material presented in the program

Cory Bernardi said the review did not examine all material presented in the program Bill Shorten says he would trust teachers over MPs with children's welfare

University of Western Australia academic professor Bill Louden last night briefed a group of about 30 backbenchers about his review of the program, which teaches school-aged children about sexual and gender diversity.

But far from allaying the concerns of Coalition MPs, the review appears to have hardened their opposition, with one telling the ABC the Education Minister needs to "fix" the program or resign.

Others have slammed the review as a "joke" and a "fraud", telling the ABC Professor Louden was given very limited scope, and just two weeks to examine the program.

Liberal-National MP George Christensen still believes Safe Schools should be axed and said he would be writing to the Prime Minister as early as today to express his deep concerns.

"That will be calling for the program either to be axed outright, or the funding to be suspended pending a full blown parliamentary inquiry," he said.

"I understand that that letter will get a lot of support from the backbench, perhaps even majority support from the backbench."

Liberal senator Cory Bernardi told the ABC the review did not examine all of the material made available to students through the program, some of which he said was "age inappropriate" and would "horrify parents".

He claimed the "innocuous-sounding" Safe Schools program actually provided links to sadomasochism sites and encouraged 12 and 13-year-old children to experiment sexually.

"Given the narrow terms of reference, there may be certainly a circumstance where a broader review, a parliamentary review could be implemented," he said.

"There is clearly a lot of unrest amongst my colleagues that they're not satisfied that the review was comprehensive enough and there's a lot of elements of it that weren't adequately explored."

Education Minister Simon Birmingham commissioned the review earlier this month after a group of disgruntled backbenchers raised concerns about the program during a party room meeting.

He said he was still considering the findings.

"Nobody has said it's a sham to me, nobody has called on me to resign," he said.

Shorten says he would trust teachers over MPs with kids' welfare

Opposition Leader Bill Shorten said the Labor Party did not have access to the full review document, but he was concerned about the position Government MPs had taken.

"Mr Turnbull has to make a decision today also, is he on the side of his Education Minister or is he going to bow to the incessant relentless demands of the far right of the Liberal Party and scrap the Safe Schools program?" he said.

Mr Shorten has labelled the MPs and senators raising concerns as "the tin-foil hat brigade up in the Liberal right wing".

"I'll tell you what, if it's a matter of trusting Mr Turnbull or Senator Bernardi or some of the others like Mr Christensen from Dawson, or the teachers of Australia, I would pick the teachers of Australia with the welfare of my kids," he said.

"The idea behind safe schools is that children who are grappling with their sexuality, who are dealing with the toughest issues teenagers can in terms of bullying, that Safe Schools would provide resources for schools to be able to help students."

He stressed that schools did not have to use the Safe Schools program, given that it is voluntary.