The Labour Party says the Government is neglecting some disabled workers by scaling back how regularly labour inspectors check on their employers.
About 1000 people are paid less than the minimum wage because they have a disability that limits them in carrying out their job.
The Government says labour inspectors will assess those arrangements every two years, rather than annually.
Labour Party spokesperson for labour issues, Darien Fenton, says disabled workers must be protected from abuse.
She says the minimum wage exemptions must be reviewed at least every year to ensure the workers are being paid a fair amount.
Labour Minister Simon Bridges says the advice he has received is that the new system will be kinder on the workers because annual interviews can be very stressful and are generally unnecessary.
He says the labour inspectors will instead spend more time focusing on migrant worker issues.