The lightweight jockey will be available to ride at the last four meetings of the current season, including the Colonial Chief Stakes meeting on the last day on 8 December.
Currently licensed by Racing Victoria, Mertens, will be at his second Kranji stint as he did fly in for a two-day licence in October 2018, scoring one win aboard Molineux from 10 rides.
Formerly apprenticed to former Kranji-based trainer Mick Kent, the son of former Melbourne jockey Peter Mertens has gone on to ride in excess of 300 winners in five years, including two at Group 2 level in 2017, Showtime in the Stutt Stakes and Snitty Kitty in the Caulfield Sprint, and 10 at Group 3 and Listed level.
Mertens claimed the Melbourne champion apprentice jockey title in the 2016/2017 season. He actually led that season's senior jockey's premiership for a long time, but was caught late by Melbourne multiple-champion jockey Craig Williams.
He finished 23rd on last season's premiership on 13 winners while his score throughout Victoria stood at 53 winners.
Mertens goes to scale at 52kgs.