David Cameron has said he is prepared to consider dropping the Conservatives' policy of imposing a cap on the number asylum seekers Britain can accept.
Mr Cameron became Conservative leader earlier this month
Michael Howard proposed withdrawal from a UN convention that obliges countries to admit people being persecuted on the basis of need, not numbers.
Mr Cameron told the Observer the plans would be subject to a policy rethink.
A poll for the newspaper puts the Tories nine points ahead of Labour among people certain to vote.
The Ipsos/Mori poll suggests 40% would back the Conservatives, up seven points from May, while 31% would vote for Labour - a drop of five percentage points, and 21% would choose the Liberal Democrats, a fall of 2%.
Asked who would make the best prime minister, 31% chose Chancellor Gordon Brown, 27% Mr Cameron and 13% Liberal Democrat leader Charles Kennedy.
Mr Cameron told the Observer he welcomed people fleeing persecution and was committed to granting them asylum, "taking them to our hearts, and feeding and clothing and schooling them".
While defending the Tory election manifesto, which he wrote for Mr Howard, Mr Cameron admitted there was "a very deep perception problem" about the party's handling of the asylum issue.
But he attacked former home secretary David Blunkett's "irresponsible language" on the issue of immigration.
"He was the person who talked about us being swamped," Mr Cameron told the paper.
He praised the cultural and economic benefits of immigration, adding: "We will have a big amount of emigration and immigration, but will also recognise that a responsible government needs to look at the level of net migration in terms of also providing good public services and having good community relations."
Mr Cameron's interview followed a speech on Friday in which he appealed to Liberal Democrat MPs and councillors to defect to his party.
He said Conservatives stood for "liberal values", including a commitment to green policies, localism and deregulation.
Mr Cameron called for the creation of "a modern, progressive, liberal, mainstream opposition to Labour".
But Lib Dem leader Charles Kennedy said his rival should change parties if "he meant what he was saying".