In a scathing assessment of the stadium's fan and athlete experience along with technological and location issues, the NRL even questioned whether men's and women's matches could be hosted on the same day.
Canberra's NRLW side is just two months away from playing its first game, with three double-headers slated for GIO Stadium in the inaugural season.
The NRL's submission to a parliamentary inquiry looking at how to foster and promote the significance of Australia's national capital was penned by NRL executive GM Andrew Every.
He says the stadium doesn't meet minimum requirements and new facilities in the city could change Canberra's perception as merely a regional centre.
GIO Stadium is in the suburb of Bruce, a 15-minute drive from Canberra's centre with limited public transport access.
"Despite the natural alignment to host significant national matches in Canberra, the lack of significant investment in stadium infrastructure has made the region uncompetitive for hosting such events," the NRL's submission reads.
"GIO Stadium Canberra and the national capital have lost their appeal as being a potential location for rugby league events of national significance and no longer fit-for-purpose."
Canberra hosted Women's State of Origin in 2022 but shouldn't expect any more marquee events before stadium upgrades, the NRL noting a lack of gender-inclusive facilities.
"GIO Stadium lacks these facilities, either entirely or in quality and quantity and with the current lack of female facilities, scheduling premier female and male events in Canberra has become unfeasible for the NRL," the NRL wrote.
GIO Stadium's major tenants - the Raiders and the ACT Brumbies - have been crying out for improvements for years, with former Wallaby and current ACT Senator David Pocock campaigning for a new stadium in the city centre.
The federal government recently pledged $240 million investment to a new stadium in Tasmania, along with another $65 million for a redevelopment of UTAS Stadium in Launceston.
Raiders champion Jarrod Croker, who's played 143 games at GIO Stadium, echoed the need for an upgrade on the ancient facilities and suggested Canberra would benefit greatly from a new stadium closer to town.
"It would be massive for Canberra ... it's probably gonna happen after I'm done, but even when I'm done, I want to come and enjoy and be able to go out in Canberra," he said.
"We speak about it every year, but it's the coldest place to be … sales are talking up near 20,000 (spectators) this weekend (against Parramatta) and it's gonna be freezing.
"Fans are tough and they've been here through thick and thin so they deserve it as much as anyone."
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