The Malta FA are currently investigating four positive dope tests, The Times has learnt. A player on the books of Premier League leaders Valletta is among the four who have returned a positive test.
The players and clubs concerned have already been notified of the outcome of the dope tests which have been carried out in recent months.
It is believed that the three players who are currently engaged with non-Premier League clubs - two in Division One and one in Division Two - have tested positive for recreational drugs whereas the result of tests on the Valletta player's sample showed abnormal levels of a hormone which is on WADA's list of prohibited substances.
The Valletta player was dope-tested after his side's Premier League second round match against Hibernians on December 26.