Former Kiwi league coach David Kidwell will help Argentina prepare for next year's Rugby World Cup.

The 45-year-old Kidwell has quit the Parramatta Eels where he was an assistant to Brad Arthur.

In what the Daily Telegraph described as a shock decision, Kidwell will assist Argentina coach David Cheika, the former Wallaby boss.

"Cheik was pretty clear, he thought I'm the guy he wants as a defensive coach but was clear that he needed me this year," Kidwell said.

"It's weighed on my mind. It's not in my character to quit on a contract…it was clear this wasn't an opportunity that I could pass.

"It's building the squad and our plans for the (2023) World Cup so I need to be there.

"I'll never say never to coming back to the NRL but I'm really excited for this opportunity.

"If I didn't take it now, I'd regret it in my life. I'm not getting any younger.

"It's an amazing feeling knowing I'm going to the World Cup over in France. It's a global spectacle, it's the third most watched sporting event in the world and to be part of that, having that on my CV, is very exciting."

Kidwell revealed he had previous rugby experience helping Japan coach Jamie Joseph before the last rugby World Cup. He met Cheika through a mutual friend.

The Christchurch-raised Kidwell, a forward who played 25 tests, had a brief and disastrous spell in charge of the Kiwis in 2017.

His playing career included a spectacular confrontation with infamous Aussie forward Willie Mason at a test in Auckland.

He has been an assistant coach at the Melbourne Storm and Wests Tigers. Kidwell played for the Eels, Roosters, Storm and Rabbitohs in a long NRL career.

Parramatta coach Arthur said the club wished Kidwell all the best and understood what a good opportunity it was for him.