The Collingwood Football Club has been fined $20,000 for failing to disclose the details of an unlisted player training with the club late last year.

The AFL announced the sanction on Monday, saying $10,000 of the fine had been suspended until 31 October 2018.

AFL Investigations Manager Ken Wood found the club had breached the list lodgement rules by failing to register details of an unlisted player prior to them starting training with the team.

The league said Collingwood had fully co-operated in their investigation, with this and other mitigating factors taken into account when finalising the penalty.