The Napthine government has slumped to a losing position as it struggles to exert control over a deeply dysfunctional Parliament and tackle concerns about health, education and public transport.

A year out from the November 2014 election, an Age/Nielsen poll has found the Coalition trailing Labor 46 per cent to 54 per cent on two-party-preferred terms.

If this result were replicated in an election, the Coalition would be swept from power with the loss of up to 12 seats, becoming Victoria's first single-term government since 1955.

The poll of 1000 voters showed the Coalition's primary vote at 40 per cent, down from 45 per cent at the November 2010 election, with Labor on 38 per cent and the Greens on 13 per cent.