The education minister, Christopher Pyne, says students should be contributing more money towards their university education, leaving open the door open for an increase in the amount of money graduates repay through the higher education contribution scheme.

The Commission of Audit report recommended that the share of university fees that students pay should rise from about 40% to 55% and that graduates should begin repaying their debt when they are earning $32,000. At present, graduates start repaying their Hecs debt when their income is $51,000 or more.

Pyne said borrowing every dollar from the taxpayer upfront was a “great system” that he would maintain. However, he said: “I do think there is capacity for students to contribute more to their own education, especially knowing they are likely to have [an] unemployment rate below 1% and they will earn, over a lifetime, 75% more than a person without a university degree,” he told ABC TV’s Insiders program.

The minister said he was attracted to expanding to the demand-driven system to sub-bachelor courses, diplomas and associate degrees.

“I'm in favour of deregulation. I'm in favour of more competition. I'm in favour of universities being able to reach their full potential. But I'm also in favour of spreading opportunity to more students to go to university,” he said.

The government was not ruling in or out recommendations by the Commission of Audit because its response would be in the budget, he said.

On the program, Pyne said that a proposed deficit levy was not Tony Abbott’s “Julia Gillard moment”. A poll in the Sunday Telegraph said that 75% of voters thought a deficit levy would be a broken promise. Pyne said the poll showed people were not turning to the Labor party.

“The Labor party is like a drunk driver who has hit five parked cars and insists on being given the keys back because they think they are capable of driving,” he said.

“The police know the drunk driver is not capable of driving, and the public know that the Labor party is not capable of making the decisions necessary to repair the damage that Labor created after six years of deficit budgeting.”

He would not say if people on low incomes would be excluded from the proposed $6 co-payment to visit a general practitioner.

“Those people on the lowest incomes, on fixed incomes, pensions and welfare, have to be the government's primary client in ensuring they have a standard of living that a country like Australia can expect all of its residents to enjoy. So they will always be treated with the utmost generosity by government and you will see that in the budget on Tuesday week,” he said.

Asked if political donations by property developers should be banned in all states, as they are in New South Wales, Pyne said he would like all donations by organisations and corporations banned.

“I don't believe that the trade union movement, or corporate Australia, should be able to donate to political parties. I think only individuals should be able to donate to political parties, so they make the decision that, with their after-tax income, they feel strongly enough they want to support a political party, whether it is Labor, or the Greens, or the Liberal Party,” he said.