New Zealanders planning to take a quarantine-free trip to Australia should remember they will need to be isolated upon their return home, Prime Minister Jacinda Ardern has warned.

The Australian newspaper has reported Australia's Prime Minister Scott Morrison is preparing to announce deals with state governments to allow New Zealanders into Sydney and Adelaide without having to quarantine in a hotel for two weeks.

He told the National Press Club in Canberra that New Zealanders were "very, very welcome" to spend money in New South Wales and South Australia.

However, he said he would not be able to announce Australians could travel to New Zealand, as that was New Zealand's problem to solve.

Ardern told reporters at Labour's housing and resource management policy announcement this afternoon that it was still too unsafe to be opening New Zealand's borders to Australia.

"In our view we are not ready to have quarantine-free travel with Australia. They have a very different strategy to us, and so they're making that decision ... but for now we of course have to keep our New Zealanders safe."

She urged New Zealanders to spend their tourism dollars domestically, and cautioned that those going to would have to go through isolation when returning.

"I encourage New Zealanders to think about spending their dollars here locally."

She says the pressure for New Zealand to open up has been "the same the whole way through", implying that Australian states opening their borders would not affect her decision.

"The National party in particular have called for us ... to open up the border. We have resisted that because we want to keep New Zealanders safe. We will not open the borders for quarantine-free travel with Australia until it is safe to do so bc doing it too early risks losing all of the freedoms we already have in our economy."