Unions are calling on the government to say whether ministers plan to stand by commitments to give equal rights to employees in the same workplace.

The call came as a leaked cabinet memo has revealed that the government is considering scrapping plans for new employment rights in a bid to maintain business support.

The rights, thrashed out during a compromise deal with the unions last autumn, were aimed at ensuring that new workers were given the same deal as existing employees and had been backed by Stephen Byers.

Unions demanded the new laws in a bid to tackle what they see as "two-tier" workplaces where different staff have different entitlements.

But with business showing increasing signs of disillusionment with the government, Downing Street is said to be leading calls to ditch the plans in order to ensure that the private sector does not blow cold on vital PPP deals.

The leaked paper, seen by the Times, was drawn up by the Cabinet Office under the instruction of Jeremy Heywood, the prime minister's principal private secretary.

It rejects taking legislative action to tackle "two-tier" workforces, and instead suggests that employers should draw up a voluntary code of conduct on workers' rights.

The memo - which is titled "restricted - policy" - also recommends that trade and industry secretary Patricia Hewitt scraps plans to include occupational pensions in regulations governing contracted-out workers.

The move would represent a major u-turn in government thinking and comes just six months after Hewitt said that not enough was being done to protect workers contracted to the private sector.

She told the TUC conference that TUPE regulations, which set down requirements covering the treatment of staff transferred from the public sector to private firms, should be strengthened to ensure workers' pension rights were not eroded.

But the confidential memo reads: "In order to keep business on board, ministers might think it preferable not to extend the TUPE regulations but to maintain the current system."

The DTI has dismissed the reports, claiming there has been no change in policy.

"What Patricia Hewitt said at the TUC conference in September still stands and we still intend to do this. We have spoken to all the main stakeholders and will make our proposals known in due course," said a spokesman.

A spokesman for the TUC said it would be taking up the matter with Downing Street.

"We don't usually comment on leaked documents. We have asked to see a copy of the document - and if the Times story is accurate we will be taking up the matter directly with the prime minister," he said.