There are growing questions over whether returning Kiwis should pay for their managed isolation.

The government says the border isolation and quarantine system will cost $81 million by the end of June.

New Zealand Initiative Chief Economist Dr Eric Crampton says the government could provide vouchers for the cost of quarantine services.

He told Andrew Dickens it would free up spaces across the facilities. 

“The quarantine voucher would be sufficient a stay at the majority of quarantine facilities that we currently have, but if somebody doesn’t think those are good enough for them and wants a nicer stay, they’ll be able to top that up.”

Cabinet's about to consider co-payments for people in covid-19 quarantine or managed isolation.

The Prime Minister says she expects to look at the option in coming weeks.

But Jacinda Ardern says quarantine at the border will remain a bottom line to keep Kiwis safe.

"Our priority is to retain our status and to keep the restrictions away from other New Zealanders, and that means containing Covid at the border.

"That does come at a cost, but the cost of another outbreak is far, far worse."