Hearts have reported Rudi Skacel and Andy Webster to Fifa and The Scottish Football Association for breach of contract.
The unsettled duo failed to turn up for the club's pre-season trip to Austria on Monday.
The futures of both players have been in doubt for some time with the pair looking to leave Tynecastle.
Southampton have been strongly linked with the duo, with former Hearts boss George Burley keen to bring them to St Mary's.
The pair had been warned they would be in trouble if they failed to show for the trip to Austria and now Hearts have enlisted the help of Fifa and The SFA to deal with the matter.
A statement from chairman and acting chief executive Roman Romanov read: "In breach with the agreement they had with the club, these two players did not go to pre-season training and in order to protect the interests of the club we have reported this matter to both Fifa and the Scottish FA.
"We will not comment on the matter further until it is resolved."