Incumbent Prime Minister Malcolm Turnbull looks set to hold power with at least 76 of the 150 seats in the Australian parliament, the National Business Review reports.

In a late surge of postal votes, the Coalition has closed the gap with Labor in four undecided seats and extended its lead in another. Two of those seats are on Queensland's coast and the others are in Adelaide and Perth.

Labor still holds a slim lead in the four closest undecided seats but this is diminishing as vote counting continues. Labor leader Bill Shorten has not yet thrown in the towel but has conceded that Mr Turnbull will "more than likely" form the next government.

The Coalition stands to gain up to 77 seats if it takes two of the undecided seats. This would be a big contrast with the 2010 election that gave Labor only 72 seats to form a minority government that depended on the Greens and independents to pass legislation.