Mostert's commitment to Tickford Racing, which had given him his start, is uncertain after a visit to rival and fellow Ford customer DJR Team Penske's workshop.

The 27-year-old former Bathurst winner said his motivation was to win a championship and admitted he was "in a pickle" over his future.

Mostert is allowed to talk to other teams because he's off contract at the end of the season.

"For me, loyalty is a big thing in this game and Tickford gave me my start. I've got to give them the best opportunity to put their foot right," Mostert said.

"'They have shown in the past they have won championships, Bathurst, races, but I want to win a championship ... and, at the moment, we've got to do a bit more at Tickford to do that.

"I really struggled looking ahead, long term. I'm such a short-term person and this weekend is all about Darwin, trying to move forward.

"Tickford have got some stuff in the pipeline which we're hoping to roll out this weekend and fingers crossed that can edge us a bit closer to those Shell cars and keep Scotty (McLaughlin) pretty honest out there because he's doing it pretty easy at the moment."

Mostert is also looking at moving overseas to race in the Group GT3, but admits he's torn because of "unfinished business" in Supercars.

"It's kind of tough; there definitely is that international (option)," Mostert said.

"I've been lucky enough to race a bit of GT3 around the world now and you go to some awesome tracks. Laguna Seca I went to this year and that was just unbelievable - I'd only every played it on video games.

"To go tick those awesome tracks off and race these GT3 cars is something that appeals to me but I have a lot of unfinished business here in Supercars.

"I'm in a bit of a pickle with that at the moment. I've just got to work out what I'm going to do over the next couple of months."

Tickford boss Tim Edwards said he wanted the situation resolved "sooner rather than later" but was confident they could deliver Mostert the car to clinch that elusive title.

"There is a lot of deliberating going on in Chaz's head at the moment. He's been pretty open about that," Edwards said.

"Of course, we'd like to keep him but we've also got to prove we've got the goods to win a championship because that's the most-important thing to him - it's not dollars.

"I think Chaz feels a bit of loyalty to us but the No.1 thing on his mind at the moment is winning a championship and we need to deliver a car to do that."

Mostert finished the fourth fastest on Friday after Scott McLaughlin, Fabian Coulthard and Jamie Whincup topped the the second practice race ahead of him.

Australian Associated Press