Officials are blaming Thursday night's incident at the MCG on a "breakdown" in screening measures, while the AFL is promising a security review after what the players' union labelled as an unacceptable incident.
Victoria Police allegedly found weapons on the men - both of whom were on bail - inside the stadium during a search at the blockbuster AFL clash between Collingwood and Carlton in front of more than 82,000 fans.
The pair refused a request from security to leave the venue over their behaviour, which is when officers got involved, police said.
Melbourne Cricket Club chief executive Stuart Fox said the stadium's security screening units did identify items of concern, which prompted further investigation.
"Our initial internal investigation identified a breakdown in the thoroughness of the secondary and manual screening process," he said on Friday.
Fans should expect delays at upcoming events due to increased manual security, Mr Fox said.
The stadium has blamed the incident on issues with a manual security screening, vowing tougher safety measures for games over the weekend.
The MCG underwent a major security upgrade in 2024, including the roll out of artificial-intelligence equipped sensors.
AFL Player Association chief executive Paul Marsh said the incident was worrying.
"Every person who attends an AFL match, including the players, staff, and fans, deserve to do so knowing there are effective measures in place to protect their health and safety," he said.
"What occurred at the MCG last night is extremely concerning and frankly unacceptable."
AFL chief executive Andrew Dillon promised an "end to end" security review.
"The MCG worked to identify how the two men were able to enter the venue, which concluded that security personnel failed to do a thorough follow up search of the patrons after an alert from the entry point screening system," he said.
Both men will be issued with lifetime bans from AFL matches.
Police Minister Anthony Carbines said someone needed to take responsibility for the shocking security breach.
"It's concerning for all Victorians, that people would enter the heart of the sporting precinct at the MCG with firearms and that's not acceptable," he said.
Both arrested men were on bail at the time.
Roxburgh Park man Omar Salma, 21, faced court on Friday morning.
He was remanded in custody until his next court appearance on April 16, charged with firearm offences and breaching bail.
Broadmeadows man Mohamad Noori, 27, faced court later in the day and will next appear on May 5, on six charges including possessing a loaded firearm and failing to appear on bail.
Counter-terrorism police were initially called to assess what happened, but the probe is now in the hands of the crime investigation team.
Prime Minister Anthony Albanese praised the officers involved in the search and described it as "pretty shocking".
"Frankly, I hope that they get the book thrown at them for this and I do want to thank Victoria Police for their work in keeping people safe," he said.
AFL Fans Association president Ron Issko said he believed crowds would back any security upgrades.
"I'll be going to the footy this weekend and I've got all the confidence in the security and the police at the footy," Mr Issko told AAP.
"Ninety-nine per cent of fans are great. If we've got some ratbags let's get rid of them," he said.
The MCG's security upgrade included a fit-out with the AI-powered Evolv Express system.
"Evolv Express uses sensors combined with AI to differentiate between weapons and common metals people carry," according to the company's website.
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