Turnout was huge for the poll, which could decide whether Slovakia rejoins the race for integration into the European Union or Nato, or slips further into isolation.
The opposition bloc looked set to take 93 of the 150 seats in parliament, while Mr Meciar's Movement for a Democratic Slovakia, with his allies in the far-right Slovak National Party, will have 57 seats.
However, the opposition bloc is united by little more than hostility to Mr Meciar. The four parties will find it difficult to find a common platform.
Mr Meciar's party claimed victory as the single largest party in the Bratislava parliament. Vice-chairman Sergej Kozlik said the party had "won the election and will behave like a winner. There is no reason for Prime Minister Meciar to quit".
Mr Meciar, a bullish nationalist, has been criticised for his authoritarian style and poor record on human rights.Reuse content