The Director-General of Health says there do not need to be zero Covid-19 cases in Australia for the border to reopen.

There are continuing calls for the trans-Tasman bubble to begin, with the Deputy Prime Minister Winston Peters saying it couild happen state by state.

Ashley Bloomfield says that the concern for the trans-Tasman bubble is ongoing community transmission in some states. 

He told Heather du Plessis-Allan that the key thing is an agreement between the New Zealand and Australian governments. 

"We are seeing low numbers of infection there, which is good, a position we were in in New Zealand two or three weeks ago." 

Bloomfield says that having zero cases is not a requirement for opening the borders with Australia. 

Currently people arriving to the country need to self-quarantine. About 250 people can come into the country each day, and there's capacity to quarantine about 3200 people at one time.

Bloomfield told du Plessis-Allan that finding more quarantine facilities is currently the Ministry of Health's responsibility for the next two or three weeks, but he has not been told specifically to find more quarantine facilities. 

"That very much depends on the number of people coming in," with Bloomfield noting that a new facility has been set up in Christchurch due to new Singapore Airline flights into the city. 

From today, people in managed self-isolation and quarantine won't be able to apply for exemptions to attend funerals and tangi.

They will still be able to apply for compassionate leave to visit a dying relative, but they won't be able to attend a service.

Someone who may have been exposed to Covid-19 overseas now poses an even greater threat to New Zealanders under alert level 1, Ashley Bloomfield says. 

On balance, Bloomfield says they thought this was an appropriate trade-off with the risks.

People should contemplate the change of rules before deciding to come back to New Zealand if it applied to their reason for returning, he said.

He said the change in rules had been part of the Government's preparations for alert level 1 and was an important measure for tightening border restrictions.