A plan to ship workers in from overseas to help in the Christchurch rebuild is being slammed as lazy, but some workers groups are welcoming the changes. 

The government is hoping to plug a gap of 5000 construction workers by announcing they'll extend visas for migrants in lower-skilled jobs from one to three years, with more flexible terms.

An accreditation scheme will also be introduced for labour hire companies.

Labour's immigration spokesperson Sue Moroney maintains New Zealanders should be trained for available jobs, particularly when unemployment is so rife in parts of the North Island.

"They've had plenty of time to prepare for it and I think this is a really lazy approach from the government," Moroney says.

However, migrant groups argue that the new scheme will actually help to avoid problems of accommodation and worker exploitation.

With no regulations, Canterbury Business Association CEO Mukorombindo says that the door was open for cowboy companies which "created a lot of hardship and indebtedness, uncertainty in contracts, accommodation headaches."

"It wasn't managed and that created problems in the community."

Mukorombindo says it would be great to see the policy work alongside council policy "talking proactively about worker accommodation solutions for the city...because that will remain an issue if we continue to recruit those workers."

EPMU Construction Organiser Ron Angel agrees that the plan may help reduce exploitation, and the union is keeping an eye on progress.

"There already are cowboys in the market who are making life difficult for immigrant labour," Angel says. "They treat them like rubbish, they flick them off as quick as they can."

Aside from benefiting the recovery, Angel believes one year visas have been a stress on the workers coming in.

Canterbury Employers Chamber of Commerce Skilled Migrant Advisor Lana Hart claims the one year visas were problematic, but the changes will help "clear the pipeline."

"It has been a bit of a challenge for businesses to keep the number of staff that they need on site to keep things moving and this flexibility is really going to open up the pipeline."

"The early signs are that this accreditation system is going to be helping address the problems that arise when migrant workers come over [and] there's no more work and they get let go because of the failure to attract the contract."

New Zealand Building Industry Federation Chief Executive Bruce Kohn is surprised by the announcement, saying the industry is telling him more specialised workers are required.

Kohn also sees workers helping with the Christchurch rebuild ending up in Auckland and helping to fix their housing crisis too. He argues that once agreements are made between government and the Auckland Council, there will be a huge demand for construction workers in Auckland too.

"Any workers who come to New Zealand get trained in our systems and workplace practices. At least if they come to Christchurch they do know there is a future in the building industry, and in Auckland particularly."

Kohn claims there are shortages in some areas, particularly around structural engineers, plumbers, electricians, and specialist tradesman.