Man had knife in AFL Lions' MCG changeroom

A man had a knife in his bag while visiting the Brisbane Lions change rooms during Saturday's clash with AFL leaders Collingwood, prompting a security review at the Melbourne Cricket Ground.

The Melbourne Cricket Club (MCC) said two men entered the Lions' change room without proper authorisation about an hour before the clash with Collingwood and remained there during the first half.

One of the men is believed to be a former employee of the Lions and the other his guest.

The club realised the men were trespassing and alerted MCC officials, who called police to remove them.

A police search found one of the men had a knife in his bag but the MCC said it was never taken out of the bag and was not used in any way.

MCC chief executive Stephen Gough said an investigation showed the men entered the stadium legally and were inadvertently given access to the rooms by Brisbane Lions officials.

"We will review our access procedures and also work with the AFL and its clubs to ensure only authorised personnel gain access to the team change rooms in future," Mr Gough said.

Collingwood midfielder and AFL Players' Association vice-president Luke Ball called for improved security at match venues.

Ball said the incident was "a bit of a concern".

"It's a pretty rare occurrence. I wouldn't think we'd need to panic or anything like that," he told reporters on Monday.

"It might be just a nice little reminder for the security measures at the grounds to tighten up a bit there."

The premiership favourites held open training sessions during last September's finals series, and Ball says similar events next month shouldn't pose too many security issues.

"You'd hope that the thousands of people that get to watch us train are all Collingwood supporters and no one would be there to cause any harm for the players," Ball said.

"But it is something that you probably need to be wary of a little bit, and hopefully they become a bit more vigilant with those sort of things now."

Police said they arrested a 44-year-old Melbourne man in the rooms about 8pm (AEST) on Saturday but released him pending further investigations.