Leeds claimed a hamstring injury prevented him playing in the 1-1 draw against Venezuela in Caracas.
A club statement read: "This decision has shown a complete lack of understanding and compassion towards Mark, whose father Joe is still critically ill over in Australia and to Leeds United Football Club who, given Mark's personal circumstances, had no hesitation in granting him unlimited compassionate leave so that he could be at his father's bedside."Furthermore, having not trained for three weeks whilst in Australia, Mark complained upon returning to Leeds of pain in his lower back and tightness in his hamstrings.
"Leeds United Football Club and Mark Viduka have following his selection for this game been open and honest with ASA and given his loyalty to both club and country it is difficult to understand why such a hard stance has been taken which does not appear consistent with that for those other players who, for whatever reasons, did not travel to Caracas.
"Leeds United Football Club are fighting a battle for survival both on and off the pitch, have just 13 games to secure their place in the Premiership and, given the stance taken to date by ASA, they now face the prospect of taking on Manchester United at Old Trafford without the services of one of their key players.
"Leeds United Football Club is taking legal advice and will explore every available avenue in seeking to redress this potential injustice."
The ASA however stated that they accept the difficulties involved in travelling across time zones and are to establish a base in Europe. Many of their top names play in Europe and their March 30 friendly against South Africa is to be played at Loftus Road.