CROWDS of up to 2,000 at some matches contributed to the GAA's dramatic suspension of club games across Ireland.
The association's management committee cited a number of recent incidents for the decision "in the interests of public safety", which applied with immediate effect from yesterday.
Club social centres and bars are also set to close and the directive will apply to all ages and grades in clubs across the island.
The GAA said: "In particular, post-match celebrations and a lack of social distancing at certain events have proved disappointing and problematic."
There was criticism yesterday of crowds at the Derry senior club football final between Slaughtneil and Magherafelt at Bellaghy.
Police confirmed they are investigating potential breaches of Covid-19 restrictions after complaints were made about a lack of social distancing by some spectators on Sunday.
Immediately after the match Derry GAA took to its Facebook page to thank its volunteers "for their assistance in hosting our games over the past number of weeks", describing the event as "superbly marshalled".
It later defended its handling of the all-ticket game, saying it had taken measures - including switching it from Derry city after stricter regulations were introduced in the area - to ensure Covid-19 guidelines were followed.
Crowds of more than 1,000 have been reported at several club championship games in Ulster, while there was also criticism last month when Dungannon Clarke's supporters invaded the pitch following their Tyrone football final victory.
Cork hurling club Blackrock was also criticised yesterday for appearing to breach social distancing guidelines after it claimed its first county title for 18 years.
Footage that emerged on social media showed players and fans marching through the town in close quarters without wearing masks.
Cork GAA said "anything that threatens... safety, and the very continuation of the game during Covid-19, needs to be avoided at all costs. To that end, we would plead with all clubs and supporters not to engage in celebrations that breach current guidelines."
Sinn Féin South Down MLA Sinead Ennis welcomed the GAA's move yesterday, saying it "shows responsible leadership which prioritises the health and wellbeing of local communities".
"This decision is not easy for the GAA and will be difficult for clubs and supporters but it is recognises the seriousness of the situation we are facing."
Health minister Robin Swann said he was "disappointed and angry" at scenes of spectators appearing to breach Covid-19 regulations.
He told the assembly he welcomed that the GAA had now suspended all its games, but is concerned about the impact the event could have.
DUP Mid Ulster assembly member Keith Buchanan also said while he welcomed the decision, "many people may see it as closing the stable door after the horse has bolted".
"We await to see what impact this game might have on the spread of Covid-19 within the community. Further answers... are also needed from the GAA as to how this situation was allowed to happen."
First minister Arlene Foster also welcomed the GAA's decision, saying other sporting codes have been able to comply with risk assessments.
PSNI Superintendent Mike Baird said: "We are aware of the GAA matches in Bellaghy yesterday and will be reviewing all available evidence to determine any potential breach of the Health Protection (Coronavirus Restrictions) Regulations NI 2020."
