A senior Turnbull government minister has rejected Tony Abbott's claim the coalition is "on a loser" if its schools funding plan disadvantages the Catholic sector.
The former prime minister expects the package - labelled Gonski 2.0 - will be vigorously debated by Liberal and Nationals MPs when parliament resumes next Tuesday.
Labor has seized on coalition dissent as it ramps-up opposition to the government plan.
Watch: 'Stare-down' over Gonski 2.0
"It should be junked - any proposal that takes more than $22 billion away from our schools over the coming decade will hurt Australian children," opposition education spokeswoman Tanya Plibersek told reporters in Sydney.
After earlier casting doubt on Labor's commitment to restore the lost funding, Ms Plibersek said the opposition would "fight until the last day" for the $22 billion.
"Judge us on our record and you will know that we will restore funding to our schools."
Ms Plibersek confirmed Labor would support the government's cuts to 24 wealthy schools and reduced funding for 353 other schools.
Mr Abbott waded into the debate during a visit to Mandurah Catholic College south of Perth on Thursday, telling students any move to "relatively disadvantage" independent and Catholic schools and advantage public schools was wrong.
"Knowing a little bit about politics I suspect that the government will decide that it's on a loser if it does anything that looks like it's disadvantaging Catholic schools," he said.
Watch: Catholic education sector upset at cuts
But cabinet minister Christopher Pyne insisted Catholic schools would pocket a billion dollar increase in spending over the next 10 years.
"So how anybody could feel they are losing when they are getting a billion dollars extra is beyond me," he told Nine Network.
Acting Prime Minister Barnaby Joyce denied any coalition MPs had contacted him to express concerns about the plan, adding it was a matter for the joint party room.
The government's package will ultimately increase federal money for schools from $17.5 billion in 2017 to $30.6 billion by 2027.
