The Wallabies' World Cup plans have taken a hit with the surprise resignation of attack coach Scott Wisemantel.

Wallabies coach Dave Rennie attempted to convince Wisemantel to stay on with the France tournament looming in September.

Offering valuable experience, he has played an assistant coach role in the past four World Cups, working with Australia, Samoa, Japan and England, who he helped to the final in 2019.

But Rennie's first lieutenant said he wanted to spend more time with his young family and focus on his business interests outside of rugby.

"Scott's a top man and one of the best coaches I've ever worked with," Rennie said in a statement.

"He's hugely respected around the world, has a mountain of experience at international level and an incredible rapport with our players.

"While we did all we could to try and keep Scott, we respect his decision and wish him, Gabs and the girls all the best."

Initially, part of the Australian set-up in 2004, Wisemantel rejoined the Wallabies ahead of the 2020 international season.

He said it was a "difficult decision" but felt it was the right one for his family.

"The World Cup is the pinnacle of our sport and requires 100 per cent commitment and that's something I'm unfortunately unable to give at the moment," Wisemantel said.

"I've loved being with this team under Dave and wish them all the best for their season and in the World Cup later this year."

The Wallabies only managed five wins from 14 games and suffered a massive injury toll with Rugby Australia announcing a review into the program.

It's not believed that Wisemantel was a casualty of that with his position secure for the World Cup.

Rugby Australia has started the search for his replacement.