Speaking at the season-opening Adelaide 500, Seamer has put to rest any fears about how General Motors' announcement of the iconic car brand's retirement would impact the future of the series.

Holden's fate being confirmed this week still came as a shock to the motorsport community, but Supercars has long been preparing for life without the famous Commodore.

"I think we, Holden and Triple Eight (Race Engineering), everybody communicated towards the end of last year that we knew we were only going to have the Commodore until the end of (2021)," Seamer told reporters.

"As far as we're aware, it's a year early.

"What we do really, really well is fast, loud, brilliant motorsport entertainment and we'll do that irrespective of what cars are out there.

"The closeness of the racing, the entertainment, the music; it's not going anywhere."

Plans for the Supercars' next generation of cars have been underway for some time, with a view to them being unleashed in 2022.

Seamer said Supercars was open to a new car being on the grid next year, but would not make any rash decisions.

"Everything's on the table and that's part of the process that we're going through over the next couple of weeks," Seamer said.

Commodore ZBs dominate the grid this year with 16, compared to eight Ford Mustangs.

But it's been Shell V-Power star Scott McLaughlin who has powered to the last two championships in his Ford.

There were four Nissan Altimas on the grid last year, even after the Japanese manufacturer pulled out of Supercars at the end of 2018.

But Kelly Racing has switched to competing in Fords this year.

Australian Associated Press