Officials are begging people who aren't already on Auckland city's islands to stay where they are.
There have been reports of boaties arriving on islands, breaching lockdown orders intended to stop the spread of COVID-19.
The killer virus has already ended the lives of two Kiwis and more than 100,000 people around the world. The lockdown, which has been in place for two weeks, bans all non-essential travel - but comes at Easter when many people like to get away.
Kelly Klink of Ngāti Rehua Ngātiwai ki Aotea told RNZ people were arriving on Aotea/Great Barrier Island, calling them "pirates" and begging the Navy to stop them.
"They're coming ashore, and that's why we're asking that they don't come ashore anymore. Our people - Ngāti Rehua Ngāti Wai ki Aotea - are very vulnerable on the island.
"[Police] can ask them to leave but whether they do, that's up to them. There are no processes in place where they can't come ashore.
"We just want some sort of safeguard for us out here, especially for Ngāti Rehua Ngātiwai ki Aotea people."
Auckland Council said the city's police maritime unit has conducted a number of patrols around Aotea and other islands since the country moved to pandemic alert level 4 in late March.
The rules are "quite clear in that recreational maritime activities – like boating or fishing – are not permitted at this time," said Insp Grant Tetzlaff.
It's not just about preventing the spread of COVID-19, but reducing the risk of injury - the fewer people in hospital and emergency departments, the more resources that can be put into treating people who catch the highly infectious respiratory disease.
"We appreciate the temptation to get out on the water for the long weekend, however, we do ask the boating community to stay home during the lockdown," Auckland Emergency Management group controller Kate Crawford told Newshub.
"This is to ensure your own safety as well as ensure we don't create unnecessary work for our emergency services, and also to prevent the spread of COVID-19 to isolated parts of Auckland, like Aotea/Great Barrier Island."
She said everyone should be following the Government's advice to stay home as much as possible.
"We need to stay vigilant at this moment, and do our bit to stop the spread of COVID-19."