Exit polls gave his Social Liberal Union (USL) about 57% of the vote, as compared with just 19% for President Traian Basescu’s Right Romania Alliance (ARD).
Victor Ponta said: “This is a clear victory with an absolute majority.”
But he will have to share power with Traian Basescu, whose term runs until 2014.
Official results are not expected until Monday.
Victor Ponta and Traian Basescu have been locked in a power struggle since Ponta came to power in April following the collapse of the previous centre-right government.
The two men have argued over control of state television and the Romanian Cultural Institute and attempts to draw up a new electoral law.
Political decision-making has at times been paralyzed.
In July, Victor Ponta suspended Traian Basescu and tried to impeach him. But a referendum failed to meet the required turnout.
Traian Basescu hinted before the election that he might refuse to re-appoint Victor Ponta as prime minister. He has described him as a “mythomaniac”.
Romania is the second poorest member of the European Union, which it joined in 2007.
The country and neighbor Bulgaria, are under special EU monitoring because of concerns about judicial independence, corruption and political influence in state institutions.
Romania is trying to negotiate a new loan from the IMF to replace the existing one which expires early next year.
w3ePexgVnM4Image source: Wikimedia Commons President-elect Donald Trump celebrated his election victory at the Ultimate Fighting…
Millions of voters across the US chose to return Donald Trump to the White House…
Donald Trump declares victory in the US election as he addresses jubilant supporters in Florida.…
Stocks around the world are rising as Donald Trump appears to be on the cusp…
Donald Trump has won Pennsylvania, North Carolina and Georgia and taken a lead over Kamala…
Quincy Jones, the celebrated musician and producer who worked with Michael Jackson, Frank Sinatra, Ray…