Prime Minister Malcolm Turnbull has promised to make company tax cuts an election issue, despite admitting the Government does not have the votes to pass them now.

The Coalition has committed to pushing ahead with the plan and Mr Turnbull says he would welcome an election on the matter — setting up tax cuts as a major political issue.

Labor is opposed to cutting the company tax rate from 30 to 25 per cent and Opposition leader Bill Shorten has pledged to repeal the cuts if they do go through before the next poll.

On Wednesday, Independent South Australian Senator Tim Storer told the Parliament he had not been convinced to support the bill in its current form.

He and Victorian Derryn Hinch were the two undecided senators who could not be convinced, despite lobbying from the Finance Minister Mathias Cormann and big business groups.

Senator Storer argued for a broader discussion about the "overall sustainability" of the tax system.

He said the revenue that would be lost by cutting company tax would be better spent providing for a rapidly growing population.

Senator Storer argued it would be better spent on infrastructure, education, health and measures to reduce inequality.

We continue to inch forward, Treasurer says

Treasurer Scott Morrison said the Coalition had come closer to passing the company tax cuts than many thought it would.

"You take these issues one step at a time," the Treasurer told 7 30.

"It was six weeks ago that One Nation said they would never support this. We addressed those issues and we made a lot of progress.

"We intend to make a lot of progress".

Mr Morrison said his Coalition partners would continue to lobby the Senate after the Easter break.

The company tax legislation will not be debated again until the May budget week, and if it is not passed then it will have to wait until mid-June.

Infrastructure tipped as big-ticket budget item

The ABC has learned infrastructure projects will be the big ticket items in the May budget, but the cash influx will come with a condition.

The Commonwealth is willing to fund major projects, such as the Ring Road upgrade in Melbourne, but only if it gets a share in road toll income.

This more assertive approach to infrastructure funding will extend beyond roads, to rail projects and public transport.

It is aimed at stopping a repeat of the Toowoomba Bypass, which saw the Commonwealth pump more than $1 billion dollars into the build, only to see the Queensland Government slap motorists with up to $30 tolls.