Roads Minister Duncan Gay is standing firm in the face of fears that stiffer penalties for cyclists will dampen people's appetite to leave the car at home and ride.

With the new fines in place in just over a week, murmurs of discontent are even coming from the big end of town where large companies have built bigger and swankier changing rooms and showers – often referred to as "end-of-trip facilities" – to cope with a rapid increase in cyclists in recent years.

Marianne Foley, a principal and board member of Arup Australasia, said the multinational firm actively promotes riding to work because cycling was a key to an active and sustainable transport system.

"We support safety measures, but increased barriers to cycling have been proven in studies to potentially reduce safety for all cyclists, which no one wants," she said.