Labour has maintained a five-point lead in the latest national opinion poll but the Liberal Democrats slumped to 8% as the UK Independence Party consolidated third place.
The Conservatives dropped one point on last month down to 31% in the survey by ComRes for the Independent on Sunday and the Sunday Mirror, with Ed Miliband's Opposition seeing the same decline to stand at 36%.
Ukip picked up one point to reach 15% as the anti-EU party continued its recent strong showing.
The Lib Dems - engaged in a fight with their Tory Westminster coalition partners to retain the Eastleigh seat vacated by disgraced ex-cabinet minister Chris Huhne - were three points down.
Other parties rose by four points to 10% but ComRes noted that it had changed methodology to include only those more likely than not to vote for all parties and not just Labour, the Tories and Lib Dems.
Despite retaining an overall advantage, Labour will be dismayed to see a reduction in public faith in the party's ability to manage the UK economy.
The proportion trusting Prime Minister David Cameron and Chancellor George Osborne to "make the right decisions" on the economy rose from 25% to 27% while those disagreeing fell from 55% to 51%. Mr Miliband and shadow chancellor Ed Balls' ratings went the other way - with support falling from 21% to 20% and distrust rising from 52% to 55%.
A separate poll showed mixed news for the Government over its plans to reduce housing benefit for claimants who have a spare bedroom in council and housing association homes. By a majority of 46% to 35% they said the principle of the change - dubbed a "bedroom tax" by critics - was "only fair", the ComRes survey for the Sunday People showed.
But clear overall majorities said that its implementation should be delayed for a rethink on how to implement it (52%), that it should only apply if people refused smaller homes (60%) and that it should not apply at all to Army families with children away on active service (77%).
For both polls, ComRes interviewed 2,002 British adults online on February 13-14 2013.