An infectious disease expert says our radical new travel restrictions came at the right time.

Since 1am this morning, anyone travelling here from anywhere but the Pacific Islands must self-isolate for 14 days.

David Murdoch told Kate Hawkesby New Zealand came out earlier than most with tough rules for travellers.

"I think this was a brave, bold move but it actually is certainly justified in the situation we're in."

He says behaviour is already changing as the country grapples with the impacts of the coronavirus rippling around the world.

"You can already see people's behaviour changing, and that's going to be part of a collective community response on the back of the public health response, which is really important, all the cough hygiene, the hand hygiene etc."

Murdoch says he thinks rules around schools and gatherings will ramp up in the coming days.