The Land Transport Department has announced it will introduce "big bike" driver's licences next year for motorcycles with engine capacity of 400cc or more.
Sanit Phromwong, director-general of the department, said the new regulation would not have retroactive effect.
Next year, applicants for big bike licences would have to be at least 18 years old, to ensure they were mature enough to prioritise road safety and strong enough to control a powerful vehicle, he said.
At present, the standard motorcycle licence applies to bikes of all sizes and the youngest age is 15 years, although legally they are restricted to 110cc until age 18.
Holders of big bike licences could also ride smaller machines, so would not need two licences, he said.
Kamol Buranapong, deputy director-general, said society had demanded stricter regulation of big bike riders for safety reasons. Other countries also had specific driving licences for different kinds and sizes of vehicle.
Training and tests for big bike licences would be tougher than for conventional motorcycles, he said.
As of July, 166,868 big bikes were registered nationwide.