Federal Government budget cuts will cause an increase in domestic violence and substance abuse, Democratic Labour Party Senator John Madigan says.

Senator Madigan, who met with Treasurer Joe Hockey to discuss the budget last week, says the budget targets people in society "who have got the least".

"The Government [is] targeting their savings on those people on lower incomes," he told the ABC's Insiders program.

"I'm being asked to contribute for three years, they're being asked to contribute indefinitely, and I don't believe that's fair."

He says that by targeting low-income earners, the Government could be increasing social problems like vandalism and drug use.

"If we attack those people with the least, I believe we're going to have more domestic violence, drug and alcohol abuse, vandalism, mental health problems and what's the cost of that going to be to mop that up?" he said.

"It's bad enough now. It's out of control, a lot of these problems.

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"I'm not suggesting that we know that we can eliminate these things but I can tell you ... this budget, I believe, will exacerbate all of these problems and more."

Mr Hockey is trying to convince the crossbench – which includes Senator Madigan – to pass key measures in the budget.

Senior Government frontbenchers have not denied reports the paid parental leave (PPL) scheme has been shelved for the rest of the year while the Government tries to pass the budget.

Negotiations over university changes could take months: Pyne



Education Minister Christopher Pyne, meanwhile, has said negotiations over a planned overhaul of universities could take months.

Mr Pyne says he is continuing talks with crossbench senators in an attempt to win support for the Government's bid to deregulate universities.

"Some crossbench senators are open to these reforms and I think they'll vote for them; others want to talk more about what we're proposing," he told Sky News.

"Some are saying that they can see there [is the] potential to pass them with some fine tuning. Others are saying no.

"Any minister who goes to the Senate with a package and says it's either this or nothing is essentially daring the Senate to vote down their whole package.

"I don't think that's a sensible negotiating position. I want to see the whole package pass – of course I do – but I'm also realistic enough to know there'll need to be negotiations."

Former treasurer Peter Costello has said the Government should drop another controversial budget measure, the GP co-payment, because it is not going to pass the Senate.

"If the Senate is really going to vote against something, there's no point saying, 'We're right and you're wrong'," he said.

"Sooner or later you have got to cut your losses and there are a couple of measures there, I think, which won't go through.

"The $7 co-payment – it's just not going to happen, so let's move on."