Wildcat strikes are "not defensible", Gordon Brown has told those angry at the employment of foreign workers.
Hundreds of employees staged walkouts across the UK over the use of foreign staff at a Lincolnshire refinery.
The PM told the BBC's Politics Show he understood workers' fears, but walkouts were "not the right thing to do".
The Tories said they did not back the strikes either but said Mr Brown's 2007 "British jobs for British workers" pledge had been exposed as "fiction".
Unofficial "sympathy strikes" spread across the country after workers walked out at the Lindsey Oil Refinery when owner Total gave a £200m contract to Italian firm IREM.
"You'll find that no government in history is doing more to try and find ways that we can help people who are unemployed back in to work as quickly as possible"The government has called in independent mediator Acas to look into claims that British workers are being illegally excluded from engineering and construction projects, while unions have urged Mr Brown to meet heads of industry in the sectors as soon as possible.
'Undercut'
Speaking from the World Economic Forum in Switzerland, Mr Brown said instead of spontaneous strike action, "what we've got to do over time, as I've always said, is that where there are jobs in this country, we need people with the skills, developed in this country".
Tackled about his 2007 Labour conference pledge to create "British jobs for British workers" - a slogan used by the striking refinery workers - Mr Brown said: "Well, we are part of a single European market but I have always understood the worries that people have.
WATCH THE FULL INTERVIEW
"They look round and say, well, why can't we do these jobs, jobs ourselves, these are jobs that we can do.
"When, when I talked about British jobs, I was taking about giving people in Britain the skills, so that they have the ability to get jobs which were at present going to people from abroad."
Mr Brown added: "You'll find that no government in history is doing more to try and find ways that we can help people who are unemployed back in to work as quickly as possible."
Health Secretary Alan Johnson said EU laws guaranteeing employment rights had been "undermined" by two recent judgements in the European Court of Justice and the government would push for action at a European level if it was proved British workers were being "undercut" by cheap labour from other parts of the EU.
HAVE YOUR SAY
"If workers are being brought across here on worse terms and conditions to actually get jobs in front of British workers, on the basis of dumbing down the terms and conditions, that would be wrong and I can understand the anger about that," he told BBC One's Andrew Marr show.
"These various judgments have distorted the original intention and we need to bring in fresh directives to make it absolutely clear that people cannot be undercut in this way."
But he also defended comments by Business Secretary Lord Mandelson, who warned against protectionism and said British workers were free to take jobs in Europe, saying it was "great" if other countries wanted to employ "skilled British craftsmen and women".
'Ridiculous'
Shadow foreign secretary William Hague, for the Conservatives, said the strikers were asking "legitimate questions...and we have to recognise people are very worried about unemployment now" but he added: "Strikes are never the way forward."
He said no "mainstream" party would promise "British jobs for British workers" as there was free movement of labour in the EU, which the Tories "strongly supported".
"It was so unbelievably ridiculous and silly for the prime minister to say that in the first place," Mr Hague told the BBC.
But he said people worried about their jobs could "certainly look to the Conservative Party to do more to promote employment and combat unemployment than is being done in this country at the moment".
Derek Simpson, joint general secretary of the Unite union, told Sky News that growing industrial action demanded solutions.
"It's certainly unofficial, it can't be sanctioned by the union, it hasn't been organised by the union, but whether you call it indefensible or not I think a lot of people will find it understandable in the circumstances."
Acas chief executive John Taylor said it was at the initial stages of its investigation into the wildcat strikes originating in Lincolnshire.
He said: "We hope to start a more detailed investigation on Monday.
"We'll also be talking to employers and unions regarding a wider inquiry into the issues around 'contracting-out' on large construction projects."
But Gordon Brown is facing calls to push for an urgent change in EU law to protect the interests of British workers.
Labour MP Frank Field, co-chairman of a cross-party group on immigration, said: "This form of contract clearly cannot go on - where contracts are awarded and there's free movement of companies but those companies then restrict who can apply for those jobs.
"That clearly has got to change and tomorrow [Monday] I hope he'll make an announcement, saying that if that is the law, then the law in the European Union is actually going to be changed."
Nigel Farage, leader of the UK Independence Party, which campaigns for the UK's exit from the EU, said it was "misleading" to suggest Acas could resolve the issue: "It doesn't matter how many meetings are held, how much or how loud anyone shouts, there's nothing anyone in this country can do."
^ Back to top | BBC Sport Home | BBC Homepage | Contact us | Help | ©
~RS~q~RS~~RS~z~RS~47~RS~)