All 1,076 test results from Tuesday's pop-up testing centre in Queenstown have come back negative according to WellSouth chief executive Andrew Swanson-Dobbs. 

The Ministry of Health yesterday afternoon confirmed all but seven tests had been processed and returned a negative result.

Andrew then confirmed to the Otago Daily Times later that all the tests were negative. 

The pop-up community testing facility - both drive-thru and walk-thru at Frankton Pak'nSave - was organised to check whether there had been any community transmission of the virus. 

It followed the positive test of a person on arrival in South Korea on July 22, who had visited Queenstown from July 1-4.

Director-general of health Dr Ashley Bloomfield cautioned that people should remain vigilant.

On Wednesday, he told RNZ's Morning Report that it was a "matter of when, not if" New Zealand got community transmission.

And yesterday, he updated the ministry's advice on face masks, saying they will be an important component of the government's strategy going forward. 

They will provide "an extra line of defence", he said.

"We are asking members of the public to view face masks as another important component of their emergency preparedness kits.

"Masks are one tool in the toolbox to help reduce the risk of spread between people. 

"Our elimination strategy is of course still based on strong border protection, testing, contact tracing, isolating people who are infected and of course . . . physical distancing."

Masks do not need to be medical grade, and can be homemade. The ministry will work with the health system to provide medical-grade masks to those who need them.

There are 12 million masks available. Currently it is not necessary to wear them, but that could change and become part of the alert level system.

Ashley in a video message had encouraged Queenstown residents to get tested, and they turned out in their droves, with queues for both the drive-thru and walk-thru testing throughout on the day from 8.30am to 5pm.

It is more than 10 weeks since the last active case in the Southern District. 

Yesterday, about 30 workers and residents in Milford were also tested. The traveller had also visited there. The results are expected back tomorrow. 

One previously reported case is now considered to have recovered, so there are now 23 active cases in managed isolation facilities, and none of those people are receiving hospital-level care. 

The number of confirmed cases remains at 1,219.

Yesterday laboratories processed 5,020 tests, bringing the total number of tests completed to date to 482,929. There were 290 swabs taken in managed isolation and quarantine facilities yesterday. 

"This rise in testing numbers is really encouraging and we are grateful to everyone that has come forward to be tested – please continue to seek advice on getting a test if you have cold or flu-like symptoms," a ministry release states.

"Thank you also to the many people including health professionals involved in taking swabs, processing them, and organising testing facilities."