AFL clubs have to be honest with fans about variable ticket prices for high demand games, the national consumer watchdog says.

Some general admission club members had to pay $39 extra to attend a high-profile game, on top of their annual membership fee.

The Australian Competition and Consumer Commission (ACCC) says the AFL's marketing did not make it clear some games would cost more.

"It is important that consumers considering whether to purchase an AFL or club membership are making this decision on the basis of complete information about the cost and benefits of membership," ACCC chairman Rod Sims said on Thursday.

After media reports and the ACCC's intervention, the AFL stopped charging the extra fees from round 15. A number of AFL clubs also changed the wording on their websites.

The extra costs were imposed on AFL members and general admission AFL club members who attended "reserve" classified games.

The additional ticket prices varied between $7.50 and $39.

Mr Sims said the ACCC would monitor the AFL's marketing and pricing, with any further problems risking potential $1.1 million fines for each contravention of the law.

AAP