A spike in shocking cases of exploitation has put the plight of migrant workers in the media spotlight. But these latest stories are part of a longstanding issue that's sometimes flown under the radar.

A spike in shocking cases of exploitation has put the plight of migrant workers in the media spotlight. But these latest stories are part of a longstanding issue that's sometimes flown under the radar despite the efforts of a few journalists.

On Monday, Nick Truebridge sat in the Newshub at 6 studio after it aired his story about 40 migrant workers holed up in a Papakura house without food.

"I've got to say as a Kiwi it was pretty embarrassing standing there last night," he told presenters Samantha Hayes and Mike McRoberts. "I don't think any of us should accept this as normal."

Truebridge followed that with another story the following night about four more substandard properties crowded with migrant workers.

He took the Newshub camera on a tour of one of the houses, revealing crammed bedrooms and broken pipes leaking sewage under the house.

That seemed less than ideal, and Truebridge explained the migrants had been subjected to these conditions after trying to find a better life under the Accredited Employer Work Visa Scheme.

He's not the only one who's been covering the plight of workers suckered in by offshore immigration agents illegally selling non-existent jobs under that scheme, which Immigration NZ acknowledges is a "higher trust model" than the six visa options it replaced a year ago.

At RNZ, Lucy Xia has been telling the stories of migrants allegedly exploited and left all-but destitute after being told they're heading into decent jobs.

One of those victims, Keisha Kung, told Xia she survived on instant noodles and foraged food after travelling to Dunedin for work that never materialised.

On Wednesday the New Zealand Herald's Lincoln Tan reported that 164 accredited employers are under investigation for migrant exploitation.

At his newsletter The Kaka, Bernard Hickey has called the proliferation of immigration scams a symptom of our "churn and burn" economy.

"There was a time New Zealand, or at least its former PM John Key, aspired to become the 'Switzerland of the South Pacific' - providing high-value financial services to the world's richest families.

"Instead, we've become a version of the Dubai of the South Pacific - allowing fraudulent agents and fly-by-night firms to bring in desperate and poor workers with suggestions of high-paid jobs and residency, only to pull the rug out from under their feet and leaving them indebted and even more desperate," he wrote…

Go to this episode on rnz.co.nz for more details