There are fears small to medium businesses will be left out of the government's latest plan to bulk up the country's construction workforce.

A KiwiBuild Skills Shortage list is in the works in a bid to lure at least 30,000 overseas workers to our shores to help build the 100,000 homes promised.

Auckland immigration lawyer, Aaron Martin says the existing accreditation status model rests on sizeable employers making applications.

He questions whether it'll even be a good fit for the building and construction sector.

"You have in New Zealand, a lot of small to medium business enterprises that are involved in property development and sometimes doing quite substantial numbers."

There's no reason the proposed list should take six months to implement.

Under the plan, construction companies can be pre-approved and hire companies accredited so they can hire overseas workers quicker.

Martin says the framework's already in place - and he's baffled as to why we'll have to wait till the end of the year for it to kick off.

"I am hoping that the reason for the delay is so that the Government consults with the building construction sector to make sure that they get their policy settings right."