Thousands of employers have been failing to pay Kiwisaver contributions building up more than $20 million in KiwiSaver debt to workers.
Labour wants them chased down with the urgency used when workers or beneficiaries owe money.
Inland Revenue figures show 11,241 employers had KiwiSaver debt totalling $24.9m at the end of June.
That debt includes $12.32m in contributions taken from workers' pay packets, $9.34m in employer contributions and $3.24m in penalties and interest.
Employee contributions not passed on to Inland Revenue by employers are guaranteed by the Government.
However, the $9.34m in unpaid employer contributions must be chased up by Inland Revenue and there are no guarantees of payment.
Labour's finance spokesman Grant Robertson said the entitlements were hard-earned.
"Employers not paying their fair share threatens to further undermine confidence in the retirement scheme after National has spent years hacking away at it.
"It is not a small amount to workers and will grow considerably after decades earning interest.
"Inland Revenue is quick to chase workers and beneficiaries that owe money. [Revenue Minister Michael Woodhouse] should direct it to chase defaulting employers with the same rigour."
An Inland Revenue spokesman said if an employer resisted paying the owed contributions action could include an application for liquidation, bankruptcy or prosecution.
"Recovering of unpaid amounts can also include placing deduction notices on other funds held by an employer, registering caveats and mortgages over properties, and obtaining personal guarantees or solicitors' undertakings."
Woodhouse said the debt was serious, but a small part of the more than $7 billion paid in employer contributions since KiwiSaver began.
"The vast majority of employers do meet their return filing and payment responsibilities...there are penalties for employers who have outstanding contributions."
Inland Revenue revised the KiwiSaver figures after realising those supplied to Radio New Zealand and showing a six-fold increase from 2000 employers with KiwiSaver debt last year were incorrect.
In fact, there were 15,242 employers with KiwiSaver debt last year - meaning the number dropped by 15 per cent.
In May, the Government promised not to make any further cuts to KiwiSaver after scrapping a $1000 "kickstart" payment which all members received upon signing up.
Prime Minister John Key said the Government's remaining contribution to the savings scheme, an annual tax credit worth $521, was "rock solid" and there were no plans to scrap it.
The KiwiSaver scheme, which was introduced by the previous Labour Government, has gradually been pared back over several budgets by the National-led Government.
The biggest changes came in 2011, when National removed the tax exemption for employer contributions, halved the member tax credit and raised the minimum contribution rates from 2 per cent to 3 per cent.
(As owed by 15,242 employers as at June 30)
• $12.32m in employee contributions
• $9.34m in employer contributions
• $3.24m in penalties and interest