Bates has another month to fine tune his strategy for the Australian Rally Championship opener, after it was postponed to April 9-11 on Monday afternoon.

Due to heavy rainfall in the region, event officials were unable to receive a permit from ACT Parks and Conservation Service to hold the rally this weekend.

It means Neal Bates Motorsport has more time to work on their newly built GR Toyota Yaris AP4 cars, which will be driven by Harry and Lewis Bates this season.

They were racing the clock to have them ready for testing on Friday, with the last bolts and assembly work being finished the night prior.

Bates thought the debut run in the forest went well, but also said there was a bit more work to be done ahead of the National Capital Rally - with time now on their side to improve the cars for competition.

"It went really well, like anything with a new car there's a few little improvements we need to make here and there," Bates said.

"Honestly, for it to have rolled out the way it did and feel so good straight away is incredible.

"It's a testament to the guys at Neal Bates Motorsport that a car like that can be built in Canberra, go out on its first ever run and be a really good package. I think it's amazing.

"There's still some work to go, certain things weren't quite finished on the car for Friday. We're constantly having conversations with teams several times a day to talk about what areas we can improve on.

"Considering we had such a short time frame to build two new cars, I think we're in a pretty good place. Absolutely it'll be ready."

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Bates and co-driver John McCarthy lead the field for the National Capital Rally, with the duo out to claim a three-peat at the 26-year-old's home event.

Their Toyota Gazoo Racing Australia teammates Lewis Bates and Anthony McLoughlin will start right behind them, while Shamrock Motorsport's Richie Dalton and Dale Moscatt begin third in Bates' former car.

Bates said the field, which has 34 ARC entries, was the strongest he'd seen in a long time. Although there'll be no Kiwi star Hayden Paddon due to New Zealand's travel restrictions.

"It's tougher than previous years for two reasons, first because the field is going to be hard to beat," Bates said.

"I have beaten them all before but when I was in a car that was very developed and I was used to.

"The challenge is trying to adapt to a new car as well as trying to set competitive stage time. I think I can be there or thereabouts, but I'm definitely expecting more of a fight than in previous years.

"I'm going to have to bring my a-game."

Clerk of the Course for the rally, Adrian Dudok, was pleased the Canberra event would still run in April.

"A lot of work has gone into this event and while it's unfortunate we can't run the event this coming week, to have a new date locked away so quickly is a terrific result," Dudok said in a statement.