According to News.com.au, teenagers have been turned away at the door of a heavy metal concert in Brisbane after the State Government revoked the venue's all ages licence.

Swedish heavy metal band OPETH were scheduled to play an all ages gig at the Arena in Fortitude Valley tonight, but the venue's all ages licence was revoked by the Liquor Licensing Division just days before the concert was scheduled.

Many under-18 fans were unaware of the recent licence revocation, arriving at the venue to either find out while standing in the queue, or when they were turned away by security guards at the door.

The Arena usually separates the venue into 18+ and all ages sections for an all ages event, but a recorded statement on The Arena's main contact number announced the licensing change meant under 18s would not be able to attend.

"Due to licensing constraints, (the) Opeth function has been changed to 18+," the recorded statement said.

"Under 18s are no longer allowed to attend this event."

The concert was advertised months in advance as Opeth's only all ages show, and online ticket vendor ticketek.com.au was still showing under 18 tickets on sale, at the same time as Under 18 ticket holders were being turned away at the door.

Online tickets were also on sale at oztix.com.au, but a notice there showed the gig had been changed to 18+ only, and advised ticketholders to "return to point of purchase for a full refund".

For fans who have travelled long distances for their only chance to see Opeth play in Australia, a ticket refund will be little compensation.

The Liquor Licensing Division could not be contacted for comment tonight.