The AFL described the errors, which related to Power defender Lewis Stevenson and Cats midfielder Allen Christensen, as administrative and unintentional.
League manager of TPP and list management Ken Wood said Port Adelaide had fully co-operated in the matter and advised the AFL as soon as it became aware of the error.
The Power recently reinstated Stevenson to the senior list after a long-term toe injury, but the 24-year-old had played four matches in the SANFL before the AFL formally announced his removal from the long-term injury list.
Geelong's breach related to Christensen, who was placed on the long-term injury list ahead of round one with Jackson Sheringham promoted from the rookie list in round three.
Christensen was removed from the long-term injury list ahead of round 12 so he could return from a back injury via the VFL, but this was not formally announced by the AFL, suggesting paperwork was not lodged.
Wood said both clubs' good records had been taken into account when finalising their sanctions.
