The Government says most employees will receive the minimum wage for sleepover work by the end of June this year.
The Public Service Association (PSA) said hundreds of community workers are waiting for settlement payments from the Ministry of Health more than a year after a court decision.
National secretary Richard Wagstaff said many people are owed thousands of dollars in backpay and the delays are unacceptable.
In October 2011, the Court of Appeal ruled that health and disability care workers must be paid the minimum wage for sleepover shifts.
The ministry said on Tuesday almost half of all agreements have been finalised and signed.
That will increase to about 90% of agreements by the end of June and employees will receive back wages once agreements are signed, it said.
A spokesperson said some negotiations have taken longer than expected - particularly where multiple funders have been involved.