People who have had two doses of the Covid-19 vaccine will only need to isolate for 10 days rather than two weeks if they test positive for the virus.
Those who are unvaccinated still need to isolate for 14 days, RNZ reports.
Vaccinated people who are identified as close contacts now only need to isolate for seven days, while unvaccinated close contacts need to isolate for 10 days.
The change does not apply to household contacts, who health officials say are at highest risk of catching the virus, RNZ says.
Associate Health Minister Ayesha Verrall told RNZ that the Delta strain had a shorter incubation period and that the vaccine helped viral material decline faster.
International arrivals now are only required to isolate at a MIQ facility for seven days, then complete three days of home isolation.
Non-New Zealand travellers will have to be fully vaccinated, but unvaccinated children and New Zealand adults are eligible to leave after seven days.
A record number of returnees were released from managed isolation facilities on Sunday, as the required MIQ stay was reduced.
Over 2500 returnees were eligible to leave MIQ on Sunday if they had been isolating at MIQ for seven or more days.
Joint Head of MIQ Brigadier Rose King said this was the largest release in the history of MIQ.
"Over 2400 of the eligible people are leaving MIQ today – about eight times more than we would normally see depart each day," King said on Sunday.
"This is the largest release in the history of MIQ, and a great logistical effort as we organise test results, health checks and transport back to the point of arrival for each person.