Forty-five cases of Covid-19 in Matamata have been linked either directly or indirectly to the Redoubt Bar.
Anyone who visited the Waikato town in the previous two weeks who was experiencing virus symptoms was told to self-isolate.
It was thought celebrations at Redoubt Bar on St Patrick's Day were where most caught the virus but it appeared transmission took place at the site in surrounding days.
Waikato District Health Board chief executive Dr Kevin Snee said anyone who had virus symptoms should self-isolate from their bubble.
"The number of cases will likely be of concern to some residents but if they are following the national guidance to remain in lockdown and stay in their 'bubble', they will be keeping themselves and their families safe, " Snee said.
The DHB was expecting the number to shift as people presented for assessment and contact tracing work continued.
Since Monday afternoon, around 200 people had been assessed in the Community Based Assessment Centre (CBAC) set up in the town by this evening.
Any Matamata residents with symptoms of Covid-19 should contact Healthline and their GP and visit the nearest CBAC.
People were instructed to inform CBAC staff if they had attended Redoubt Bar within the previous fortnight, or if they had close contact with anyone who had.
There were 89 new cases of coronavirus in New Zealand today, the most recorded in a single day so far.
Director-General of Health Ashley Bloomfield said it showed the country was not yet "flattening the curve" in terms of daily case rises.
It would be another week until the nationwide lockdown had observable effects on the number of cases, he said.
The 89 new cases were made up of 76 confirmed cases and 13 probable cases. It brought the total to 797 cases since the start of the pandemic.
Ninety-two people have recovered, Bloomfield said. Thirteen people were in hospital and two were in ICU.
Fifty-one per cent of cases have links to overseas travel. Just 1 per cent were community transmission but Bloomfield expects that number to rise.
Seventeen per cent of cases are still being investigated. Bloomfield said many of those are expected to be community transmission.
There were 2563 tests yesterday – making a total of 26,000 tests so far.