Labor is losing ground in key marginal seats on the New South Wales Central Coast and Kevin Rudd's popularity is nosediving there, according to the latest Newspoll.

The Newspoll published in the Australian newspaper shows Labor support in the seats of Dobell and Robertson has fallen seven percentage points since the last federal election.

Labor's primary vote for the two seats is at 35 per cent while the Coalition's primary support is 50 per cent, a gain of eight points since the 2010 election.

On a two-party preferred basis in the two seats, Labor's support is down seven points to 46 per cent and the Coalition's is up seven to 54 per cent.

And for the first time in a Newspoll, Federal Opposition Leader Tony Abbott has overtaken Mr Rudd as preferred prime minister in the key marginal seats.

On the question of who would make the better prime minister, 47 per cent nominated Mr Abbott compared to 41 per cent for Mr Rudd.

But national polling still has Mr Rudd in front as preferred prime minister.

Today the Prime Minister will be in Perth where he is hoping to gain support in two marginal seats.

In his first visit of the election campaign to the Western Australia capital, Mr Rudd will be targeting the Liberal seats of Hasluck and Swan.

Before Labor switched leaders the party feared it could lose some, if not all, of the three seats it holds in the state, but Mr Rudd's return has boosted its confidence.

The Prime Minister flew into Perth last night after touring the Ord River region in the Kimberley region of the state.

He has promised $10 million to kick-start stage three of the Ord irrigation scheme, as part of plans to boost investment in northern Australia.

Editor's note: This story has been amended to make clear that the two-party preferred figures quoted refer to voting intentions in the seats of Dobell and Robertson.