Australia's consumer watchdog has accused the Collingwood Football Club of using ''half truths'' in an attempt to drive up its already massive membership.

The Australian Competition and Consumer Commission hit the club with two infringement notices, totalling $20,400, for advertising a membership deal that was one-sixth of the total amount that needed to be paid.

The Magpies, which has the biggest membership base in the AFL, was offering a three game membership and a Collingwood guernsey plus a free cap and scarf for $20, despite the actual price being $120.

It advertised the promotion in the Herald Sun and emailed the offer to more than 90,000 people in May this year.