BUCHAREST (Reuters) - Romania's leftist coalition government is on track to secure a big parliamentary majority in an election this weekend, an opinion poll showed on Wednesday.

The vote is being closely watched because Romania hopes to negotiate a new loan deal from the International Monetary Fund once its current 5-billion-euro funding package expires next year.

The survey, by pollster IMAS, suggested Prime Minister Victor Ponta's Social Liberal Union (USL) would win 60.5 percent of the vote. That was up from a previous poll which put its support at 57 percent.

The poll suggests Romania will avoid any potentially unsettling uncertainty and that the political landscape will remain largely unchanged.

Analysts have said there could be turbulence if there was an upset and no one group succeeded in winning an outright majority because centre-right President Traian Basescu nominates the premier and might choose one of his allies in such a scenario.

The same poll suggested that the Right Romania Alliance (ARD), a new grouping of centre-right parties dominated by the opposition Democrat Liberals, would win about 15 percent of the vote.

The parties that make up the alliance are allies of President Basescu and are unpopular for past austerity measures.

The populist People's Party of media entrepreneur Dan Diaconescu, that advocates steep tax cuts and wage hikes, would also get 15 percent, the poll showed.

The USL failed to impeach Basescu earlier this year in a bitter political battle that raised concerns over the rule of law in the European Union's second-poorest member state.

The poll, commissioned by local radio EuropaFM, was conducted between November 29-December 3 and has a margin of error of 3 percent.

(Reporting by Ioana Patran; Editing by Andrew Osborn)