The cyclist crashed on the Rameka bike track near the small Tasman town of Takaka at 2.40pm on Saturday.
Police said more information was to come.
Meanwhile, a man was in a critical condition after a motorcycle crash on a south Christchurch road.
Emergency services were called to the crash at the intersection of Dyers Pass Rd and Summit Rd in Cashmere just before 2pm on Saturday.
A St John spokeswoman, Neha Concisom, said a man was taken to Christchurch Hospital with critical injuries.
Two ambulances attended the scene.
A police spokeswoman said the road was closed shortly after the crash at the intersection of Dyers Pass Rd and Governors Bay Rd.
Police remained at the scene and a tow was called just after 4.30pm, she said.
More to come.