Young Victorian Reba Stewart's first taste of Olympics Taekwondo has ended in the round of 16, falling to Poland's Aleksandra Kowalczuk in Tokyo.

Competing in the +67kg class, the 20-year-old struggled to find her rhythm against her more experienced rival.

Kowalczuk dominated the first two-minute round to take a 4-0 lead after landing a kick to the head, with Stewart also penalised for holding her opponent.

Another kick saw the 25-year-old Pole extend her lead to 7-0 before Stewart got on the board with 14 seconds remaining in the second round, with a kick to the trunk closing the margin to five points.

Neither athlete was able to add to the tally in the final round, with Kowalczuk moving comfortably through to the quarter-finals.

Her defeat ends a disappointing campaign for the four-strong Australian team with three-time Olympian Safwan Khalil among the early casualties.