The Sydney-born player has played for the England Youth and U-20 teams and spent a brief loan spell at Coventry City last season.
McMaster has made four substitute appearances in the Premiership for Leeds.
The 21-year-old made a big impression on McFarland during a pre-season friendly last August at Saltergate in which he scored a great individual goal.
"We all remember the stunning goal Jamie scored against Chesterfield in a pre-season friendly and we are delighted he has agreed to join us to help our cause," said McFarland.
The Spireites will hope to erase the memory of Saturday's 7-0 drubbing at Plymouth Argyle when they entertain Wrexham this weekend.