Forcing tourists to take driving tests would risk retaliatory action from other countries, Prime Minister John Key says.

Questioned by media today about tourists causing road accidents, he said the situation had improved.

"They still represent a very small number of those involved in serious accidents," he said.

"A lot of work has gone on, airlines are running safety videos, car rental companies are doing a lot around trying to educate people, there is a great deal more information."

Mr Key says the education campaign must be continued.

"If we say we will require tourists to be tested we would probably have to test all of them, and I think New Zealanders would be very frustrated to find that when they went overseas they would be tested."