Greens take seat of Melbourne

It is shaping up as a momentous election for the Australian Greens after Labor all but conceded the seat of Melbourne to the minor party.

The Greens are also expected to hold the balance of power in a new Senate.

It was more bad news for Labor, which was facing the loss of a number of seats in crucial marginal electorates in Queensland and western Sydney.

Labor frontbencher Nicola Roxon indicated Adam Bandt was likely to win the Greens their second ever seat in the lower house, taking the electorate previously held by Finance Minister Lindsay Tanner, who is retiring.

Although the Greens' Adam Bandt is trailing the ALP's Cath Bowtell on a two candidate preferred basis, Liberal preferences are expected to give him an historic win.

Early counting gives Mr Bandt 4121 votes, with Ms Bowtell gaining 4631, but preferences are expected to give the Greens a swing of over 12 per cent in a seat Labor holds by 4.7.

"It's a sad result for Labor," Ms Roxon told the Nine Network.

Two hours after the polls closed on the east coast of Australia and with counting about to begin in Western Australia, which was two hours behind eastern Australia, Labor was facing a tense time.

It was showing significant losses in Queensland and NSW but was doing relatively well in Victoria, Tasmania and South Australia.

Foreign Minister Stephen Smith believes it could all come down to WA, where three seats could hold the key to the election.

With 40 per cent of the national vote counted, Mr Smith told ABC Television Labor had "clearly lost" six or seven seats, and was at risk in 10 or 11 more.

"We could end up looking at how we go in Hasluck and Swan and Canning as being really crucial," he said.

"On all the available evidence you would proceed from the starting point that we would just fall below (a majority).

"Those three (seats) may end up being quite crucial to the overall complexion of the night."

The coalition needs 17 Labor seats to win the election by garnering a uniform swing of 2.3 per cent across the country.

But the government can lose its absolute majority if it loses 13 seats.

Labor may need to talk to Greens

Labor powerbroker Mark Arbib says his party may have to work with the Greens to form government.

"This is a bad night for the Labor Party," he told the Nine Network.

"We're now looking like we have to talk to the Greens."

Mr Arbib said there was "no doubt" that for Labor to win government it would have to pull through on a number of seats, including Lindsay, Greenway and Swan.