The Government has announced 500 spaces a fortnight in managed isolation will be allocated over the next 10 months - the majority for skilled and critical workers.

The Government already has a policy for at least 10 per cent of MIQ spaces to be given to these workers – out of roughly 4500 fortnightly – but this announcement means 500 would be set aside for certain groups on a targeted basis.

The announcement was made at today's post-Cabinet press conference.

The trans-Tasman bubble had freed up more MIQ rooms, allowing more places in managed isolation to be allocated for critical workers, Covid-19 Response Minister Chris Hipkins said.

"It has given us flexibility to expand our engagement with the rest of the world on a targeted basis and attract skills and people needed to drive our economic recovery, while carefully managing risks of bringing in Covid-19.

"We're now at the stage in our Covid response where fewer New Zealanders are choosing to come home, which gives us the opportunity to focus MIQ more on bringing in skills to support our economic recovery."

The trans-Tasman travel bubble opened up on April 19, and New Zealand's quarantine-free travel bubble with the Cook Islands will begin on May 17.

The Government was averaging more than 10 per cent of MIQ spaces set aside for economic purposes per month, as promised at the election, Hipkins said.

Under the new policy the 500 rooms would be made available for "large groups" every fortnight.

This included around 300 workers under the Recognised Seasonal Employer (RSE) scheme every month from June – with 2400 arriving by March 2022.

Another 240 specialised construction workers between June and October, 400 international students in June (out of the 1000 previously announced), and 100 refugees every six weeks from July.

Hipkins said it was "great news" for the construction sector and would help deliver critical infrastructure work.

"It gives certainty for planning projects with specialist workers from overseas, maintains construction jobs for Kiwis and will bring new knowledge to New Zealand for employers and employees."

Further work under the Construction Sector Accord would take place to prioritise the specific types of skills it needed, he said.

"They include civil and structural engineers, project managers and a range of specialist technical workers such as hydraulic modellers and mass transit specialists.

"We've also renewed border exceptions for shearers, rural mobile plant machinery operators and essential travellers to and from the Pacific."

Those workers would need to book spaces through the online Managed Isolation Allocation System, he said.

Agriculture Minister Damien O'Connor said the moves would provide the agriculture, horticulture and viticulture sectors the additional workforce they needed, with continued worker shortages despite training and upskilling New Zealanders.

The extra 2400 more RSE workers in time for next summer's harvest season and pruning this winter were in addition to the 7300 RSE workers currently in the country, including the 2000 the Government approved to support the horticulture and viticulture industries during the recent summer harvest season, he said.

Exceptions have also been agreed for 40 more shearers and 125 rural mobile plant machinery operators for the 2021/2022 season, subject to labour conditions, he said.

The allocations would be balanced on seasonal and strategic skills shortages, seasonal variations of when overseas New Zealanders travel home, and international obligations, such as providing hundreds of MIQ places for the United States Antarctic Programme over the winter months, Hipkins said.

Around 20,000 vouchers will be made available in the online Managed Isolation Allocation System over the next three months for New Zealanders wanting to return home, he said.

New Zealand's "strong" Covid-19 response and the vaccine roll-out had made these moves possible, he said.

There have long been calls from businesses to allocate spaces for critical and skilled workers in MIQ, rather than have them compete in the general ballot.

Act Party leader David Seymour has said the Government should have had a plan ready to go ahead of the trans-Tasman bubble.

"You can't keep having the attitude of 'better late than never' when being late is causing so much pain to business owners, causing delays to important projects and left families separated.

"There was no need for us to miss the entire 2020 season as the Government stood by watching fruit rotting on the ground."

Seymour said more work needed to be done to utilise all MIQ spaces.

This week there would be 1798 empty MIQ rooms, a similar number to last week, he said.

"The Government will give itself a big pat on the back today when it should be reflecting on how much misery it's caused businesses when it should have been working proactively to have a plan in place."