Migration by low-skilled workers into the UK is too high and action must be taken to reduce it, Labour leader Ed Miliband said on Thursday.
Miliband's comments came as he identified immigration as one of the areas where New Labour made mistakes in government, and as he came under pressure to explain how he would do things differently.
As Labour's annual conference in Manchester drew to an end, Miliband said he discussed his keynote speech with elder brother David before delivering it on Tuesday, and received a message of congratulations from his former leadership rival afterwards.
Miliband insisted that he and his brother were now "over" the period of difficult relations that followed his victory by the narrowest of margins in the 2010 leadership contest.
He brushed off reports that David might be invited back to co-ordinate Labour's campaign for the 2015 general election, but repeated his position that he would like to see his brother back on the party's frontbenches at some point.
Polls today indicated that Miliband's bravura no-notes speech, in which he attempted to claim the political centre ground by stealing the One Nation mantle from moderate Tories, had boosted his standing with voters as a potential prime minister.
But questions were also being asked about the absence of policy detail in the speech on key issues like immigration and welfare.
In an end-of-conference interview with BBC Radio 4's World at One, Miliband made clear that he was concerned about British workers being under-cut by migrants on less than the minimum wage.
The Labour leader said: "I think in terms of low-skill migration, I think it is too high and I think we need to do something about it."
He added: "The issue that has not been properly addressed by politicians is when people come into the country, particularly from eastern Europe, are they coming in a way that has economic benefits not just for the country as a whole but for people in it across the board, or is it being done in a way that is used to undercut people already here and exploit those coming here, when you have got the abuse of the minimum wage or gangmasters in the construction industry who are abusing the rules?
"The difference between my approach and the last Labour government is that I am less sanguine about the effects when people come in. I am clear that if we have an open Europe - which we have and I don't think any political party is proposing going back on that at the moment - we have got to make sure we have the toughest standards of rights at work and make sure they are properly enforced."
Miliband was dismissive of the Government's cap on immigration, which does not include migration by EU nationals. And he declined to state how many migrants he believes should be allowed in, saying: "It is very hard to say in the abstract precisely what level of immigration you want."
With Miliband acknowledging that there would have to be spending cuts under a Labour government, there has been speculation that he might strip benefits like the winter fuel allowance and free bus passes from wealthy pensioners.
But he today played down this prospect, saying: "You always have a balance between universal benefits and means-tested benefits. I don't particularly think the balance is in the wrong place at the moment.
"Of course you have got to look at these things, but for me the issue is much more do you want to be giving a £3 billion tax cut to the richest people in the country while you are raising taxes on other people? I don't believe we should be doing that."
Miliband has summoned his shadow cabinet colleagues to an away-day retreat later this month, at which they will be expected to deliver policy ideas to put his One Nation Labour approach into practice.
He insisted that the label was more than a fleeting slogan: "It is a whole political approach, I believe, One Nation Labour, which will take us through into the general election and I hope into government."
He defended his decision to attend a TUC anti-cuts rally on October 20, saying: "The TUC rally is about people of concern right across the country who see this approach of austerity isn't working."
Miliband said his brother's decision to leave Manchester ahead of his speech, in order to avoid being a "distraction", was a sign of "his loyalty to me and his loyalty to the party".
Two years on from his narrow victory in the leadership battle, Miliband said Labour was now the most united major party in the UK.
And he added: "I talked to David this week before my speech, about my speech, about what was going to be in my speech. We talk quite a lot about the issues that we face in politics.
"The contest two years ago was a difficult time for us. We are over it and I think the Labour Party is too."
Miliband added: "He doesn't want to come back to the shadow cabinet at the moment. He feels he is pursuing his own set of projects as part of the Labour Party family.
"I totally respect that judgment. I would like him to be back on the frontbench at some point and I make no bones about that.
But that is a judgment we can make over the coming years, and I don't think the position is about to change."
Miliband's comments on immigration come after shadow immigration minister Chris Bryant told The Huffington Post UK Labour's immigration policy couldn't be defined in a "nutshell".
"It's not in a nutshell. You can't do it in a nutshell and I don't want to do any of it in a nutshell. In the end there's about 30 different issues that impact upon immigration," he said.
As the conference came to an end with the traditional singing of the Red Flag, Miliband left Manchester to meet potential swing voters in Corby, Northamptonshire, where Labour is hoping to overturn a narrow 3.6% Conservative majority in a by-election expected to be held on November 15. Before leaving, he paid a brief visit to the set of ITV soap opera Coronation Street.