ROME (REUTERS) - Italy's centre-left coalition will win a majority in the lower house of parliament, but the upper house will be deadlocked, the Interior Ministry said on Tuesday after almost all votes were counted.

After 99.9 per cent of the polling booths had been tallied, the centre-left led the centre-right by about 125,000 votes in the lower house, handing it a sizeable majority thanks to a generous winner's bonus.

But the Senate was a different story. The centre left was sure to win more seats than the centre right in the upper house, but fell well short of a majority, even in coalition with outgoing Prime Minister Mario Monti's help.

Since both houses are needed to pass laws, the centre left would need the help of comic Beppe Grillo's 5-Star Movement or Mr Silvio Berlusconi's centre right to pass laws, currently an unlikely prospect.

If no agreement can be reached, a new vote would have to be called.