Oil prices rose this evening as the US dollar weakened due to optimism that Greek Prime Minister George Papandreou's cabinet would survive a confidence vote, reducing the possibility the country would default on its sovereign debt.

Brent crude was up 21 cents to $114.90 a barrel, while US crude bounced off the fresh four-month low of $91.14 it touched on Monday, trading up 60 cents at $94.86.

The dollar weakened as the euro gained, with investors optimistic Papandreou will win the crucial confidence vote. A weaker dollar usually makes oil cheaper for holders of other currencies.

The vote is required to secure backing for a new round of spending cuts, tax hikes and state asset sales for a €12 billion lifeline from the EU and the IMF.