"Full-time drivers like me will be hit because we don't have a second income to depend on," he said.
Uber said it was now offering a "ride-share" service so its drivers did not need professional licences.
Drivers would just need to have held a licence for two or more years, use a car no older than 2006, have their criminal and driving record checked and hold third-party insurance.
But the NZ Transport Agency does not accept that Uber is operating a ride-share service, and has warned that drivers found to be transporting paying passengers without proper endorsement licence risk a $500 fine.
The agency says Uber's new driver requirements are illegal.
Mr Kang said drivers will be writing to Uber urging it to stick to the old fares and to not put drivers in a position where they were breaking the law.
"We will give Uber three working days to respond, and if we do not get a satisfactory answer than we will plan to strike," he said.
An Uber spokesman has said the fares were dropped to attract more customers so drivers would have "more bums on seats" and earn more fares.