Low pay, understaffing and customer abuse are causing major concern across the grocery industry, according to a survey of more than 1500 supermarket and grocery workers from major retail chains.

The survey - completed electronically in May through First Union's member database - shows thousands of supermarket workers are grappling with the high cost of living.

They are also dealing with regular incidents of customer abuse in understaffed supermarkets that are typically paying the majority of workers less than the living wage.

Union national secretary for retail and finance Rudd Hughes says workers hailed as heroes during the Covid-19 pandemic are no longer treated that way by employers.

More than 70 per cent of those surveyed say their wages are not sufficient to cover living costs, and more than 60 per cent of a sample size of 1514 workers say their pay rises over the past two years have not kept pace with rising costs.

Only 21 per cent say if they received an unexpected $500 bill tomorrow, they could pay it.

Rudd says the National-NZ First-ACT coalition's repeal of fair pay agreement legislation denied workers a pathway to negotiate minimum standards across the supermarket industry.

"They've offered up a paltry tax cut, whereas fair pay agreements would have actually made a real difference to workers' wages."

The survey shows 69 per cent of workers have considered quitting in the past two years, and on top of this, 90 per cent say their stores are understaffed.

"Understaffing is a major contributor to workers' stress and burnout, and it makes supermarkets much more unsafe workplaces for staff than they should be." 

Abuse of staff by customers and other incidents of violence and dangerous behaviours at work were a growing problem, and more likely to occur with fewer staff around.

More than a third of those surveyed reported being verbally assaulted or threatened at work, and 30 per cent say they have had to confront thieves in their stores.

Another four per cent say they have been sexually harassed or assaulted, and two per cent say they have been spat on.

"No one should have to deal with regular and sustained danger and abuse at work, and least of all those who aren't even paid a living wage and have few prospects for improvements in the workplace," says Rudd.

In February, Foodstuffs announced up to 25 Pak'n'Save and New World supermarkets will be using facial recognition technology to try and combat rising thefts and violence against staff.

Rudd says the survey's findings will be key in outlining minimum standards for the union's upcoming bargaining with all supermarket major chains.

-RNZ.