Ed Miliband has promised new measures to prevent British people being "locked out" of jobs by foreign workers, including forcing firms to declare if they employ high numbers of immigrants.

Overseas-only employment agencies would be banned and an early-warning system set up to highlight areas where locals are "dominated" by an influx of overseas labour under the proposals.

While there cannot be set quotas on home-grown workers, urgent action is required to identify where British jobseekers need better training to compete, said the Labour leader. Demanding that job centres be told of all firms where more than one in four staff is from overseas would form part of the new system to provide Whitehall and town halls with vital information.

Mr Miliband hopes to shift the focus of the debate from border controls, and what he says are ineffective Government caps on arrivals, towards the impact on people's daily lives. While restrictions on new arrivals, including caps on people from any new EU member state, are necessary, reforming the jobs market is just as important, he argued.

Mr Miliband distanced himself from the rhetoric of his predecessor Gordon Brown, saying: "I am not going to promise 'British jobs for British workers'. But we need an economy which offers working people a fair crack of the whip. The problem we need to address is in those areas and sectors where local talent is locked out of opportunity."

He said Labour had to change its approach to immigration and recognise "the costs as well as the benefits", arguing the last Labour government under Mr Brown became "too disconnected from the concerns of working people".

"We too easily assumed those who worried about immigration were stuck in the past, unrealistic about how things could be different, even prejudiced. But Britain was experiencing the largest peacetime migration in recent history, and people's concerns were genuine. Why didn't we listen more? At least by the end of our time in office, we were too dazzled by globalisation and too sanguine about its price."

In a further pointed swipe at Mr Brown, he said people who expressed legitimate concerns about immigration should be engaged with, not dismissed as "bigoted". The former PM damaged Labour's 2010 election campaign when he was caught on microphone using the term about a voter he met in Rochdale. "Worrying about immigration, talking about immigration, thinking about immigration, does not make them bigots. Not in any way," Mr Miliband said. "They're anxious about the future. And since this conversation is going on in the houses, streets and neighbourhoods of Britain, it must be a conversation that the Labour Party joins too."

Immigration minister Damian Green said: "Until Ed Miliband supports the Government's measures to cut and control immigration, Labour will have no credibility at all. Under his leadership, Labour have opposed our aim to get annual net migration down to the tens of thousands, and they have opposed the cap on economic migration, our changes to student visas and our reforms to family visas. They refuse to admit that immigration is too high, and they refuse to say immigration needs to come down.

If Ed Miliband thinks the national minimum wage is the solution to immigration, he needs to explain why, after introducing the minimum wage, net migration increased by 2.2 million under Labour. He says he isn't going to promise British jobs for British workers but he seems to have fallen into the same trap as Gordon Brown. He still opposes everything the Government is doing to cut and control immigration and still isn't offering a single credible immigration policy of his own."