Malcolm Turnbull has declined to say if he will take his company tax cut policy to the next election.
Speaking on the ABC's 7.30 program on Monday night, the Prime Minister said he would try again to negotiate with the Senate crossbench when Parliament resumes next week, to win their support to cut the company tax rate from 30 to 25 per cent.
Labor has campaigned furiously against the proposal, saying it will only benefit the big banks, multinationals and the big end of town, which includes the independently wealthy Mr Turnbull.
Speaking after the recent round of byelections, where Labor held on to two critical marginal lower house seats, Mr Shorten said the result meant voters had rejected Mr Turnbull's "rotten corporate tax cuts".
The results, combined with the difficulties of the on-and-off again response from One Nation's Pauline Hanson, whose votes are critical, have spooked some government MPs who think the government should rethink the policy.
Mr Turnbull on Monday said that he would try again to get his policy through the Senate next week, but declined to say if he would campaign for the cuts at the next election if he fails with the crossbenchers.
"We have a mandate from the last election, we took it to the last one," he said.
"Australia needs a competitive tax system. We are going to approach this issue, as we always do, with respect and constructive negotiation with the crossbench. We have to work with the realities of the Senate."
He said the government would "of course" be refining and tweaking its policies before the next federal poll.
Labor's treasury spokesman Chris Bowen said: "If Malcolm Turnbull drops the company tax cuts - that’s he’s spent two years selling as his one point economic plan - he’ll be exposed as standing for absolutely nothing."
Australia and Mexico have the third-highest tax rates in the OECD behind only France and Belgium and the four countries are the only OECD economies with company tax rates set at 30 per cent or higher.
In recent years, right-wing governments in the United Kingdom and United States have cut their rates to 19 and 21 per cent respectively, while Canada's company tax rate is just 15 per cent.