Those satisfied with Deputy Prime Minister Nick Clegg have increased from 26% to 31% and with Labour leader Ed Miliband from 33% to 41%. All three party leaders have a net negative approval rating, however, with more people saying they are dissatisfied than satisfied with each of them.
And none of the main parties is judged by a majority of voters to put the national interest ahead of their own. Some 69% think the Tories put their own interests first, 63% the Liberal Democrats and 59% the Labour Party.
Just over two-thirds of voters - 67% - think the coalition is disunited and 54% feel it is unlikely to last until 2015, as planned. Only 39% think it will go the distance until the scheduled next general election.
Ipsos Mori's head of political research, Gideon Skinner, said: "The party leaders and the Government are benefiting from an upbeat public mood generated by the Olympic Games.
"Even this, however, cannot overcome public scepticism that the coalition is divided, and that all parties tend to put their own interest above the national interest. The question is whether this feel-good factor will last."