He remained in a critical condition on Sunday but is now in a stable condition in ICU on Monday.
Police are seeking information from anyone who saw the two motorcyclists before the crash.
Police Eastern District road policing manager Inspector Matt Broderick said the crash was one of at least six on Saturday and Sunday in the region.
About 7pm on Sunday night, emergency services were called after a car rolled at the roundabout on the Hawke's Bay Expressway at the intersection of Longlands Rd and SH50A.
A police spokeswoman said one person was treated by ambulance at the scene for a sore back and a tow truck uplifted the vehicle.
Earlier on Sunday, about 4.30pm, emergency services were called to a two-vehicle crash on Waimarama Rd.
A Fire and Emergency spokesman said no one was trapped and there appeared to be no injuries.