The workers said they were owed payments at penalty rates under a clause of the Multi Employer Collective Agreement in respect of meal breaks not taken.
They said the DHB should be ordered to pay a penalty in respect of breaches of the Employment Relations Act, the Holidays Act and the collective agreement.
Workers said their employer had neither complied with the Act nor the collective agreement in that no rest and meal breaks were provided.
However, the DHB said it complied with both the Act and the collective agreement in respect of both rest and meal breaks, pointing to the presence in the rosters of the provision for another person to "cover breaks" for the workers during week days.
In her decision, Ms Monaghan said the person who covered the meal breaks did so on the basis she would be available at the start of the evening shift on Mondays to Fridays so, in any event there was no coverage on night, weekend and holiday shifts.
There was conflicting evidence about whether the person provided sufficient cover for a 10-minute break or a 30-minute break. The workers said the cover was sufficient only for a 10-minute break, the person providing cover was expected to provide it at the end of her day's work, and she was not available for the full 30 minutes.
After the investigation meeting, that person provided an affidavit saying she provided 15 to 20 minutes' cover.
The authority found that if the cover provision in the roster was intended to provide cover for a 30-minute meal break, the period of cover was not specified in the roster and the authority was not satisfied it was observed in practice.
"For these reasons I do not accept the board's submission that staff on the evening shift received a paid meal break at the commencement of their shift on weekdays," Ms Monaghan said.
The DHB said workers could take rest and meal breaks at their work stations which was permissible under the act and collective agreement.
Ms Monaghan said there were constraints on the workers' ability to take any other break, meaning the workers were tied to their work station.
She said eating and drinking at a work station did not amount to a break.
She reserved any decision on costs, giving parties 28 days to file a claim.