JOHN Longmire has urged the AFL to invest more time, money and energy into growing the game, warning that cuts will hurt the next generation as the sport reaches a critical point in Sydney.

The AFL reported a $22.8 million loss after wrestling with the financial fallout of COVID-19 in 2020, with job losses affecting head office, clubs and grassroots programs.

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Sydney and crosstown rival GWS's combined loss totalled more than $10 million over the same period.

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Swans coach Longmire praised the AFL for "saving the game" and navigating an uncertain consolidation phase.

But Longmire, among the sport's most respected figures, says the League must now shift focus to long-term planning and "get a feel for what's happening on the factory floor".

I've seen when it was shunned as a sport up here; when an AFL ball would be confiscated by staff at schools

- John Longmire

Coaches and club staff are doing more as they make do with less; one of the attractions of new Swans assistant coach Don Pyke was that he boasts coaching, business, boardroom and admin experience.

Longmire is wary of burnout among colleagues, but worries most about future players.

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"It's one thing to cut costs, but ultimately if you don't invest it will cost you more," Longmire told AAP.

"What does the game look like post this period? How far forward are we looking?

"The next generation of under-18 footballers; the budgets have been cut significantly. We still need those kids coming through for the growth of the game.

"We can't afford to let that die or not let recruiters have any resources because the next generation is going to suffer."

Tasmania's push for an AFL team has dominated headlines in recent weeks.

It is western Sydney that the League previously identified as a crucial battleground for hearts and minds, having created GWS with long-term plans and immediate delight over the additional fixtures that helped deliver a $2.5 billion broadcast deal.

A blitz in Sydney followed, with rugby league icon Phil Gould famously describing AFL goalposts as ''sprouting like mushrooms'' in 2011.

Longmire, who played 200 games for North Melbourne, has worked out of the SCG since 2002.

Few know the AFL's challenges in the NSW capital as well as the 50-year-old.

Swans assistant coach John Longmire with Jude Bolton and Brett Kirk after the 2005 Grand Final win. Picture: AFL Photos

"The longer we stay in 'saving the game' mode, the more steps back we take in competition for some of the best athletes and a lot of eyeballs in the northern states," Longmire said.

"I've seen when it was shunned as a sport up here; when an AFL ball would be confiscated by staff at schools.

"I've seen unbelievably significant growth. We don't want to take a backwards step now, because rugby league and rugby union won't."

Longmire's Giants counterpart Leon Cameron also urged the AFL to invest heavily in lower levels.

"The (participation) numbers have gone through the roof," Cameron said.

"I just hope they acknowledge it's harder here and in Queensland.

"You don't want to make all this ground then all of a sudden it dries up."