Swimming in the fifth and final heat, Fairweather recorded 1min 58.39s, which placed her fifth of the eight qualifiers for the final.
The qualifiers were led by Australians Lani Pallister, who beat Fairweather to the 400m gold medal, and Inez Miller.
Fairweather seemed happy enough after her swim. 'Just wanted to qualify for the final and get a reasonably good lane, so all good,' she said.
New Zealand's two representatives in the women's 100m backstroke qualified for the semi-finals. Amber George qualified ninth with a time of 1min 01.46s and Savannah-Eve Martin was the 12th qualifier with a time of 1min 01.74s. The fastest qualifier was Australian Iona Anderson, who recorded 59.86s.
The New Zealand mixed 4 x 100m freestyle team qualified third for the final. The team of Chelsey Edwards, Milana Tapper, Cameron Gray and Carter Swift recorded 3min 28.19s to win their heat and place behind only Australia and England among the qualifiers.