Drivers caught using their mobile phones while driving will cop five demerit points instead of four under a crackdown on road safety by the New South Wales Government.

Minister for Roads Melinda Pavey said the harsher penalty for illegal mobile phone use behind the wheel would make motorists think twice before using their phones.

"If you think about long weekends or double demerit periods you could actually be at risk of losing your license," she said.

A recent survey conducted by the Roads and Maritimes Service found 74 per cent of people support a tougher penalty for illegal phone use by motorists.

"We have the community's support on this," Ms Pavey said.

"Three quarters of the population that we surveyed want better and stronger road rules around mobile phone use."

Fully licensed motorists can use their phone legally to make or answer calls or listen to music if it is in a cradle, doesn't obscure your view of the road and can be operated without touching any part of the phone, such as via Bluetooth or voice activation.

The demerit change will come into effect in September, prior to the October long weekend.