Dr David Clark's van was spotted in a car park used by mountain bikers near his Dunedin home on Thursday.

The health minister may not have broken the rules of New Zealand's severe lockdown - Kiwis are allowed to drive their cars short distances and are encouraged to take part in exercising during their self-isolation.

However, Dr Clark's choice of mountain biking caused alarm as an accident would have required care by emergency health workers during the crisis.

The Dunedin North MP both told news outlet Stuff "this was my only chance to get out for some exercise in daylight hours (and) the track itself is not challenging".

"I know that now is not the time for people to be engaging in higher-risk exercise activities," he said.

"I don't want to give anyone the perception that I take these matters lightly. This is a reminder to me to think carefully about how best to fit some exercise into my new-normal routine."

While Dr Clark didn't apologise to the public, he did apologise to his boss.

"I spoke to the Health Minister last night, who apologised to me," Ms Ardern said.

"It's my expectation that Ministers set the standards we are asking New Zealanders to follow.

"People can go outside to get fresh air and drive short distances if needed, but we have asked people to avoid activities where there is a higher risk of injury, and the Minister should have followed that guidance."

Opposition leader Simon Bridges fell short of asking for Dr Clark's resignation but urged him to get his mind on the job.

"The bigger sin or crime to me frankly is him not being at his desk in Wellington as the Health Minister during the biggest health crisis in our lifetimes," he said.

Unlike in Australia, where officials in each state have issued strict guidance which spells out their list of permitted activities, in New Zealand, the government and police haven't been so explicit.

Ms Ardern has instead simply urged people to maintain strict social distancing, to "stay local" and use their common sense.

On Friday, health officials announced a fresh 71 cases, keeping New Zealand on track to reach 1000 COVID-19 cases by the end of the week.

There are 868 identified cases of the virus throughout New Zealand, though just 13 infected Kiwis currently require care in hospital.

The number of recoveries from the disease also continues to rise each day, with 103 people declared free of COVID-19.

Just one New Zealander has died in the pandemic.

Australian Associated Press