The government is being urged to name software providers implicated in potentially massive, nationwide payroll errors, to make it easier for people to find out if they have been affected.
Officials have estimated up to 760,000 people could have been underpaid over several years, with a total cost topping $2 billion.
The errors stemmed from annual leave entitlements being miscalculated after the Holidays Act was amended in 2003.
Labour's economic development spokesperson David Clark said the government was not doing enough to help the people who were now out of pocket.
"At this stage most people I've spoken to on the street are unaware they could be owed thousands of dollars, that's not good enough, people should be paid what they are due."
Dr Clark said the government should give people as much information as possible, and a good start would be naming individual software providers.
"The Minister could be very clear which payroll systems are most affected, it seems the whole way through some payroll systems have been more successful than others at guiding their employers to pay correctly.
"If the Minister released a list of those payroll companies most affected, Kiwis could go and talk to their employers and say 'look I realise that the payroll system you've been using is underpaying people routinely around the country, I would like my payment records checked' ."
Revenue Minister Michael Woodhouse said if employees and their unions found out they had been underpaid, they could seek arrears.
He said the government was actively working to fix the problem.
"Look we have the Employment Courts, the Employment Relations Authority and of course the Labour Inspectorate, so I'm satisfied there's enough in there for those who think their entitlements are not being provided for, to go and have those questions fairly considered."
Mr Woodhouse did acknowledge it was complex.
"But I think that's where the Labour Inspectorate, working with the unions supporting employees, is an important part of the process.
"Employment law is complex and it covers a wide range of of issues so yep, I think it's important people get the right advice."
The Minister's office said releasing information relating to individual software providers would not be up to him, as the Labour Inspectorate was dealing with the matter.