Kangaroos coach Mal Meninga is "heartbroken" over Australia's World Cup withdrawal, according to his assistant Adrian Lam, the Wigan head coach.

The decision of Australia and New Zealand to pull out of the tournament, citing safety fears amidst the coronavirus pandemic, has provoked anger in England, with Rugby Football League chair Simon Johnson accusing them of "cowardice".

World Cup chief executive Jon Dutton told a news conference on Thursday the chances of the tournament going ahead in the autumn were 50-50 and they receded further on Friday when the 16 NRL clubs threw their weight behind the decision of Australia and New Zealand to pull out.

Lam, who son Lachlan is expected to play for Papua New Guinea if the World Cup goes ahead, can see the NRL's argument but insists Meninga remains a big advocate of the international game.

"I know Mal is very passionate about growing the international game," Lam said. "I've seen how hard he's worked to try and develop the international game, it's unbelievable.

"The Kangaroos tour over here has been dead and buried for a very long time and it's Mal that brought it back into the forefront of international rugby league. I think it's important we acknowledge that.

"I know that he'll be heartbroken and disappointed about that but it's the bigger picture we need to take into consideration here.

"It's just a difficult time with the pandemic, there's so much grey area around it.

"There's no 'us and them', it's just the situation we find ourselves in. The NRL are currently in lockdown in Queensland because of Covid cases in New South Wales. There's that much to take into consideration."

Dutton is hoping to bypass the clubs and speak to the NRL players directly in an attempt to allay their concerns but the worry is that the hard-line stance by the clubs could affect the participation of other southern hemisphere nations who make up half of the 16 teams.

A statement from the NRL said: "The 16 clubs are united that it is in the best interests of player health, safety, wellbeing and the international game for the World Cup not to proceed in 2021.

"The support not to play is based on the high Covid-19 infection rate in the United Kingdom and onerous biosecurity and quarantine protocols that would be placed on all players having just completed a lengthy period away from home during the NRL Telstra Premiership.

"The 16 clubs support the World Cup being delayed until 2022 where it is expected there will be less risk to player health and safety and a stronger competition."

Dutton told the news conference there was "little appetite" for a postponement and said officials had began looking at bringing in Indigenous and Maori representative sides to replace Australia and New Zealand.

Lam does not believe that would provide an acceptable solution.

He added: "I can't imagine the World Cup going ahead without the two nations. It's not a World Cup without Australia and New Zealand.

"If it can't go ahead with those two countries out, I'm sure they'll make the right decision and potentially postpone it for 12 months."

South Sydney chief executive Blake Solly, a former general manager of Super League, said a 2022 World Cup would provide a better platform for players and fans.

"We all support our players reaching the pinnacle of representative football, be it All Stars, state or country," Solly said.

"We're proud of our players representing their nation, we continue to meet our obligations to players when they are on representative duty, but we also need to be sure they will remain healthy when they do.

"The NRL and its clubs have gone to great lengths and invested heavily to ensure our players remain healthy and the competition continues.

"These measures have been taken with an infection rate in Australia that is minimal when compared to the rate in the UK.

"This rate of infection is far too high for us to be confident the players will not contract Covid-19 during the World Cup in the UK."

England are due to kick off the tournament against Samoa at Newcastle's St James' Park on October 23.

A final decision is due to be made next week.