'Being over here and the opportunities I've had have swayed that dream' - Son of Wallaby legend on the brink of Brave Blossoms selection

Jack Cornelsen's father Greg made rugby history for the Wallabies but, as he prepares for a fourth season in Japan, the 26-year-old forward is eyeing a Test jersey of a different colour.

Japan's Top League will begin on Saturday after a month-long COVID-19 delay with Cornelsen's Panasonic Wild Knights to face the Ricoh Black Rams in Tokyo.

The back-rower is one of 30 Australians set to play in the 16-team competition this season - with Wallabies captain Michael Hooper among 10 of those who have played in the green and gold at senior level.

Ned Hanigan, Will Genia, and Quade Cooper are also in Japan but playing in the country's second-tier Challenge League.

Greg Cornelsen's historic four-try haul at Eden Park in 1978 - a feat no man had ever achieved against the All Blacks - is still firmly etched in rugby minds across both sides of the Tasman.

A Gold Coast junior, Jack Cornelsen said he always dreamed of following his father and fellow No.8's path to the Wallabies.

But a two-week trial at Robbie Deans' Wild Knights in 2017 changed all that.

Now eligible for Test selection for Japan, Cornelsen admits his priorities have shifted as a berth with the Brave Blossoms beckons.

"Growing up in Australia it is your dream to play for the Wallabies, but being over here and the opportunities I've had have swayed that dream at the moment," he told AAP.

"But yeah I'm prepared (sacrifice a shot at playing for the Wallabies by playing for Japan) ... I was playing club rugby in Brisbane and it was just a two-week trial to start with, but then I realised I really do like this and it's a decision I've loved now."

Importantly he has his father's blessing, even if it means Cornelsen is lining up against the Wallabies at the 2023 World Cup in France.

"He's always been supportive with anything like that, and was probably the one that said originally, when the opportunity came up, to just go and take it and see what happens," Cornelsen said.

"Looking from the outside in, Japan are a top-tier team and while COVID has changed things lately I've loved living here; the people, culture and the food."

Former Wallabies coach Deans has been at the helm of Panasonic since 2014 and the competition is set for more Australian eyeballs than ever as Hooper joins former All Blacks captain Kieran Read at Toyota Verblitz.

"I've played with David Pocock and Berrick Barnes (at Panasonic) and every week you come up against world class players," Cornelsen said.

"It's been awesome and everyone adds their little touch from where they come from, so it only helps us to pick up more stuff."