New Zealand's pause on the quarantine-free travel bubble with Victoria has been extended for a further seven days, with the Australian state going into lockdown to contain a growing Covid-19 outbreak in Melbourne

The extension of the pause on travel will take it through to next Friday.

Covid-19 Response Minister Chris Hipkins and Director-General of Health Ashley Bloomfield provided an update on the travel bubble situation.

This afternoon, Victorian government announced the state would go into lockdown for a week to contain a growing Covid-19 outbreak in Melbourne.

Hipkins says the current situation is the biggest challenge to the trans-Tasman bubble so far.

He says anybody who has been in a location of interest in Melbourne cannot travel to New Zealand for at least 14 days since visiting the location.

"We are considering whether further restrictions should be put in place. We will make decision on that in the next 24 hours or so.

Dr Bloomfield has implemented new rules under the Health Act regarding anyone who was in Melbourne from 20-25 May.

"Anyone who has travelled to New Zealand is required to isolate, be tested, and keep isolating until they receive a test result.

"We are applying a precautionary approach."

Hipkins says authorities will be attempting to contact people who have travelled to New Zealand from Melbourne since May 20.

"There is a lot of them so they shouldn't all expect to be contacted immediately,” he says.

"We are expecting around 5000.”

Contact tracing centres will be used to follow up with those 5000 people, likely starting tonight, Dr Bloomfield says.

Dr Bloomfield says they thought the risk was still quite low but the number of locations of interest that were high risk had risen a lot.

"We think it's prudent to ask anyone who has been in Melbourne to isolate and be tested."

The Australian Prime Minister's visit to New Zealand should still be able to go ahead, Hipkins says.

Hipkins is satisfied there was testing capacity for those people across the country.

New Zealand's government put the quarantine-free travel for people arriving from the state on pause earlier this week as cases began to be detected in the community.

Hipkins says the pause on travel would be kept under review.

"If the pause for any reason were to continue, then we would look to other options, whether or not we would provide emergency travel for those who needed to get back immediately".

The government has set aside some rooms in MIQ as a trans-Tasman contingency for isolating, Hipkins says.

People had been told if they travelled they may have to shelter in place, he says.

"Covid-19 does continue to dominate around the globe... we do have to expect things to continue to be disrupted from time-to-time."

The number of active community cases in Melbourne continues to rise and was at 34 at 1pm (NZ time), according to Health Victoria.

In its daily Covid-19 update, the Ministry of Health states anyone who has come over from the state and been at a location of interest at the specified time must immediately self-isolate and call Healthline on 0800 358 5453 for advice on when to get tested.

Thousands of people who recently arrived from the area have been sent an email about the situation.

"Anyone in New Zealand who has been in the wider Melbourne area since May 11 who develops symptoms while in New Zealand should also ring Healthline and arrange to get tested.

"The number of locations of interest being announced by Health Victoria is also continuing to rise and there are now 150 exposure sites across Melbourne.

"Given the time frames, it is crucial that everyone who has been in the state of Victoria since May 11 keeps checking Victoria Health's website detailing the locations of interest."

Anyone who has been in the Whittlesea local government area since May 11 should also ring Healthline for advice, the ministry said.

- RNZ