The women's four of Kerri Gowler, Grace Prendergast, Kelsey Bevan and Kayla Pratt won their heat in 6:46.420 to go directly into the final.
They beat France by 15s but in the other heat, the United States produced a slightly faster time, with China second and marginally slower than New Zealand, the times suggest a three-horse final.
The lightweight men's four of James Hunter, Peter Taylor, James Lassche and Curtis Rapley were second in their heat in 6:17.960, 2s slower than Austria, but enough to move into the semifinals.
Bourke and Stephenson finished second in their heat, recording 7:03.300, two and a half seconds slower than China's Weiwei Zhu and Yuwei Wang, with Germany third.
New Zealand crews will race again on Wednesday with that repechage and the men's lightweight double scull, men's and women's single sculls racing in quarter finals.