A government report into migrant exploitation in the Christchurch rebuild has found some Filipino workers are being taken advantage of, and small businesses are the main culprit.

The Ministry of Business, Innovation and Employment report follows a 2013 investigation into the treatment of migrant workers in the Canterbury construction sector.

The report, based on interviews with key informants and industry contacts, finds Filipino workers are particularly vulnerable to exploitation and are less likely to speak up for fear they'll lose their visa.

It concludes labour hire companies and small employers are more likely to be exploiting workers because their business has grown so fast, without the right systems in place.

In order to prevent exploitation, the report suggests holding pre-departure conferences for Filipino workers so they knew their rights in New Zealand.

It also wants those recruiting migrant workers to be supported.

But Recruitment and Consulting Services Association board member Ian McPherson claimed the report paints a picture of the industry in 2013 when the research was commissioned, and things have moved on since then.

"There's been a lot of work done subsequent to that with both direct employers and recruitment companies. The report reflects the market eighteen months ago," he said.

"It's probably not what the market looks like today."

"In the majority of cases people have looked at a sourcing channel and gone into with the best of intention and it hasn't worked out, but the steps that MBIE and Immigration have put in place over the last twelve to eighteen months I think is predominantly addressed that."

McPherson said small businesses are no longer as busy as they were, so don't have the need to hire migrant workers.