The mystery source of a Covid case who stayed at a Nelson holiday park is yet to be found. 

On Saturday, the Ministry of Health announced four new cases in Nelson-Marlborough. One person tested positive while staying at the Tahuna Beach Holiday Park between January 30 and February 5. 

A ministry spokesperson said it was not yet known how the case was linked and today revealed investigations into the source are continuing. 

Tahuna Beach Holiday Park chief executive David Pattinson told the Herald the case was a local man who stayed at the park for about a week. 

He said the park was ready for an outbreak and knew it was inevitable. 

"We had done continuity planning and everybody just did their job. 

"The ministry set up a testing station here the next morning and all staff have been tested and as many guests as possible," he said. 

All tests to date have come back negative. The holiday park is still open and operating as usual on the ministry's advice, he said. 

There was one new case announced in the Tasman region today. It is linked to a previously reported case. 

"Public Health staff are wanting to thank people at the park for the strong testing and vaccination turnout," the ministry said in today's 1pm Covid update. 

The Tahuna Beach Holiday Park has been added as a location of interest between 7am on January 30 and 3pm on February 5.