Driving for #888 Mercedes-AMG Team Triple Eight, van Gisbergen's fastest lap clocked in at 2:03.9649, ahead of Pro-AM driver Anton De Pasquale, who finished just over .200 of a second behind the Kiwi driver in a time 2:04.1684.

Speaking after the end of the fourth practice session, van Gisbergen commented on the sizzling conditions he endured in his Mercedes AMG GT3.

"The car was freaking hot, I'm telling you. I'm hating life," he said.

"The cars awesome but we're probably the only ones not sand bagging. Our two cars were up the front.

"It feels good now and we've got a good handle on what the car is doing, but it's the Europeans that have a very different style.

"They'll be hanging out until qualifying."

With the mercury peaking at almost 38 degrees on Friday and with similar conditions forecast for both Saturday and Sunday - including potential rain and thunderstorm on the latter - van Gisbergen knows there's going to be a few tough days ahead of him and his team which features Jamie Whincup and Maximillian Goetz. .

"Yeah, I don't know what to say," when asked on driving in high 30 degree conditions on the weekend.

"The heat sucks.

"It was a good start on Friday, but no one will be flat out. Everyone will be playing. It's the way this racing goes unfortunately.

"Everyone will catch up."

Taking out the third quickest time on the final practice lap was South African driver Kelvin van der Linde, who is with #222 Audi Sport Team Valvoline.

Hong Kong driver Josh Burton of #35 KCMG was the quickest driver in the first practice, his lap time of 2:06.5531 enough to pip #4 Team Australia Grove Racing's Brenton Grove.

In the second practice, it was the team of #999 Mercedes-Amg GruppeM that topped the drivers in the second practice in a time of 2:04.7819.

The team, featuring Felipe Fraga, Maximillian Buhk and Raffaele Marciello, was also the quickest in the final practice session at Mount Panorama for last year's 12 Hour, however, the team - which featured Buhk and Marciello then - finished in the main event in third.

David Reynolds, runner-up at the 2012 Bathurst 1000, was the quickest in practice three in a time of 2:04.9312.

The #75 SunEnergy1 Racing driver finished ahead of German Luca Stolz from the #77 Mercedes-AMG Craft-Bamboo.

The first practice of the day didn't go to plan for #35 KCMG Nissan Nismo GTR, as if suffered major damage at the end of the session.

It was later confirmed that the incident would rule the car out of the 12 Hour.

Racing will continue at Mount Panorama on Saturday morning, with the fifth and final 12 Hour practice session at 8.45am.

Qualifying for all classes will start at 12.40pm, before Class A qualifying only at 1.35pm.

The top ten shootout will start at 5.05pm, with the main race starting at 5.45am.