New Zealand's premier V8 Supercars racer Shane van Gisbergen is apparently on the verge of quitting his motorsport career in favour of a lower octane lifestyle back home.

The 23-year-old Aucklander is yet to comment on Australian media reports but Stone Brothers Racing are expected to issue a statement on their leading driver's future this week.

Van Gisbergen, who remains fifth overall in the competition after penultimate round at Winton, north of Melbourne, ended today re-signed with SBR in May through to the end of 2015.

He joined Gold Coast-based operation founded by New Zealanders Ross and Jim Stone in 1998 five years ago and recorded his best finish in 2011 when he was fourth on the championship standings.

When he re-committed to SBR Van Gisbergen said "it's a pretty cool feeling to be able to keep all our relationships going, I definitely think I can win a championship with SBR, that is the main reason I wanted to stay."

Six months later he is believed to have had a change of heart, possibly because the Ford-aligned driver's team is switching to Mercedes Benz AMG equipment next year as part of a merger arrangement with Australian GT outfit Erebus Motorsport.

A report on speedcafe.com said van Gisbergen was originally eyeing a switch to Charlie Schwerkolt's Ford Performance Racing next year but had now become disillusioned with the sport although he may continue to compete in the lower profile karting and quad-bike arenas.

Van Gisbergen was earmarked by SBR as a future star while racing open-wheel cars in New Zealand during the mid-2000s.

He made his debut as a 17-year-old with Team Kiwi Racing at Oran Park in 2007 and was promoted to SBR's main team the following year.

Always aggressive behind the wheel, Van Gisbergen improved his final placing each year from his first full season in 2008 where he was 15th.

In 2009 he was 12th; he cracked the top-10 for the first time in 2010 and enjoyed a breakthrough campaign last season when he won the New Zealand round in Hamilton and also at Hidden Valley.

New Zealand's Formula Ford Championship winner in 2006, Van Gisbergen was then second in the Toyota Racing Series in 2007 before transitioning to V8s.

If van Gisbergen, who has four podium finishes and a maiden pole position at Sandown on his 2012 record, is falling out of love with the sport his experience in yesterday's opening race was unlikely to influence a change of heart.

He qualified fourth fastest, improved to third on the opening corner but after just 10 laps he was forced to retire after his Falcon sustained structural damage during a collision.

Van Gisbergen fared better today, holding off teammate Tom Slade to finish fourth and maintain his position on the ladder.

Slade was fifth and trails the New Zealander by only 37 points with one round remaining, the Telstra 500 at Sydney's Olympic Park from November 30.

While Van Gisbergen and Slade were duelling for the minor placings, Jamie Whincup wrapped up his fourth title after overcoming a pit lane penalty to pick up the points required to seal the championship.

Whincup finished third after battling his way through the field after falling as low as 25th following a drive through penalty imposed after he spun his wheels while his Holden was up on jacks in pit lane.

He dropped to 22nd place midway through the 67-lap race and lost more ground during another pit stop.

Whincup eventually climbing to third with four laps remaining to ensure his only rival Mark Winterbottom cannot catch him in Sydney.

He now holds a 317-point championship lead over Ford's Winterbottom, with only 300 points left on offer this year.

Whincup's Team Vodafone teammate Craig Lowndes won and Winterbottom was second.

The 29-year-old, who has won 12 of the 28 races so far this season, adds this year's title to his 2008, 2009 and 2011 championship triumphs.

- © Fairfax NZ News