New Zealand on Friday suspended its quarantine-free travel bubble with Australia for at least eight weeks due to a growing COVID-19 cluster in Sydney.

New Zealand recently imposed quarantine restrictions on travelers from New South Wales, Victoria, and South Australia states, where lockdowns have been introduced to contain delta variant clusters.

Prime Minister Jacinda Ardern said quarantine-free travel would be suspended from anywhere in Australia from 11:59 p.m. New Zealand time.

Ardern said she hoped to have all New Zealanders who wanted to return flown home from Australia with managed flights within a week.

The travel bubble has existed since April and has provided both countries with their only quarantine-free international flights.

Both Australia and New Zealand have been among the most successful in the world in containing coronavirus outbreaks. But Sydney is failing to contain a cluster of the highly contagious delta variant, which has spread across the country.