The Service and Food Workers Union is taking action to try to ensure home support workers are paid for the time they spend travelling between clients.
The union filed a claim with the Employment Relations Authority on Friday and has asked for it to be sent to the Employment Court for urgent attention.
The union says it believes it is illegal for organisations employing home support workers not to pay them the minimum wage during time they spend travelling between clients.
John Ryall, the union's national secretary, says it has filed the claim on behalf of Wellington home support worker and union member Tamara Baddeley.
Mr Ryall says Ms Baddeley gets paid for the time she spends in a client's house, but not for the up to 30 minutes she spends driving between clients - and that is unacceptable.
"It's a test case for the whole home support sector, which we think is vastly under-funded. Workers are paid very little ... a lot of them close to minimum wage.
"They're paid money for travel allowance - that's the mileage allowance, which is below what it costs for them to run their cars, and they're not paid in between jobs."
Wellington law firm Russell McVeagh says there is a good argument that in between travel time constitutes work under the Minimum Wage Act and a test case would have a reasonable chance of success.
Judy McGregor, the Equal Employment Opportunities Commissioner at the Human Rights Commissioner, believes the issue should be tested in court.
"We would like to see resolution about fair travel and a policy that's bedded-in by the Ministry of Health so we don't have to keep coming back year in and year out fighting this particular battle on behalf of ordinarily low-paid New Zealanders who in many cases are using their own cars to deliver this vital public service."