Labour MPs have stepped up pressure on Gordon Brown over rights for agency workers ahead of a meeting on Monday.
More than one million people in the UK are employed through agencies
Backbenchers rallied enough support to get a second reading for a private member's bill to give temporary workers the same rights as permanent staff.
Mr Brown has pledged an inquiry into the issue instead, but he is to meet union leaders to discuss a way forward.
More than one million people are employed via agencies, which means they do not get benefits such as sick pay.
MPs voted by 147 to 11 - a margin of 136 - to back Labour MP Andrew Miller's bill, proposing to give agency workers the same rights as permanent staff.
Among the 136 Labour MPs who voted for the bill's second reading was former work and pensions secretary Peter Hain.
Industry leaders oppose the bill saying it will lead to job losses and damage competitiveness.
But trade unions say Labour pledged to create a "level playing field" for agency workers in its 2005 manifesto.
Tony Woodley, joint general secretary of Unite, said: "The message today sent by Labour MPs to their government could not be any clearer.
"Nothing less than primary legislation, delivered now, can quell the clamour that has come from MPs, the Labour Party's ruling body and from the wider labour movement.
"Hopefully today's vote has also quashed the idea of a commission to look into agency working.
"The evidence of the need for legislation now is overwhelming and we will not accept the promise of jam tomorrow."
Mr Miller's bill was helped on to the next stage by dozens of Labour backbenchers who took part in the debate, many of whom might normally have spent Friday in their constituencies.
Mr Miller, MP for Ellesmere Port and Neston, said he was facing the same "doom merchants" who had opposed the introduction of the minimum wage.
He told MPs: "It's in the best long-term interests of the economy to encourage employers to plan for the long term and establish a well-trained and well-motivated workforce.
"What the bill proposes is morally right. How can it be right for people to work alongside each other with the same skills doing precisely the same task and yet one category of employee is worth less than another?"
For the Conservatives, shadow energy minister Charles Hendry said the bill was "fundamentally flawed" and a "blunt instrument".
He said temporary work was "greatly valued by employers and many individuals" and praised the "thriving" agency sector, adding that many people chose to work in it for "positive" reasons, such as increased flexibility or to gain work experience.
Mr Miller's bill would give new rights to 1.4 million agency workers and the same pay and conditions as full-time employees.
But CBI deputy director general John Cridland told BBC Radio 4's Today programme the bill's approach was "scattergun" and that more discussion was needed.
In December, EU ministers failed to reach an agreement on legislation that would have given temporary workers, such as those employed through agencies, similar rights to permanent staff across Europe.
The UK opposed the proposals, saying it would damage the country's flexible labour market and hit jobs, but the legislation will be discussed again this year.
The CBI warned that new rights for agency staff discussed by the EU employment ministers would cost up to 250,000 jobs.