AAP

MASTERCHEF Australia has achieved its biggest ever TV audience, cracking the two million viewer mark for the first time.

An average national audience of 2.12 million viewers tuned in to Monday's episode of the Network Ten TV cooking competition, in which former Sydney golfer Lucas Parsons was eliminated.

The audience peaked at 2.71 million.

Featuring contestants making two pies - one sweet and one savoury - it received about one million more viewers than its rivals, soapie Home and Away on the Seven Network, and US sitcom Two and A Half Men, on Nine.

Five finalists remain - South Australian Poh Ling Yeow, Julie Goodwin and Justine Schofield from NSW, and Victoria's Chris Badenoch and Julia Jenkins, who are rumoured to be dating.

Sunday's finale is expected to break viewer records to become the most watched item on television this year.

The first State of Origin rugby league match, which drew an audience of more than 2.3 million, currently holds the top spot.

The huge ratings on Monday night helped Ten win the night with a 26.6 per cent audience share, ahead of Seven with 24.4 per cent, and Nine with a 23.8 per cent share.