Unions will run an extended campaign against the Turnbull government's $24 billion in company tax cuts, putting pressure on Labor to agree to reverse the measure if it wins the next election.

On Sunday, Labor refused to say whether it would dump the company tax cut if it wins government, arguing it needed time to discuss the issue in shadow cabinet and examine how the Coalition will pay for the package in the May budget.

The Turnbull government passed about half of its company tax cut package on Friday, which will initially reduce company taxes to 27.5 per cent and eventually to 25 per cent, for companies with a turnover of up to $50 million.

Treasurer Scott Morrison and Finance Minister Mathias Cormann have demanded the ALP say whether it will unwind the cuts - which would mean raising taxes for about 880,000 businesses - or keep the package it has campaigned against.