Last week, the ASX-listed company AP Eagers released a statement admitting to underpaying workers over a seven-year period due to anomalies in its payroll system identified in a company-initiated review.

The company self-reported to the Fair Work Commission and pledged to fully cooperate with any investigation of the matter.

IN OTHER NEWS:

There are more than 400 Motors and Webster Trucks employees in Tasmania. An AP Eagers spokesman said 282 current and former Tasmanian employees had been "potentially impacted" by the underpayment.

It's understood approximately 170 of those are active employees. The spokesman said communications had been sent to past and present employees to notify them of whether or not they'd been affected.

Australian Manufacturing Workers' Union state organiser Jacob Batt said workers knew they may have been affected but were as yet uncertain as to whether they themselves had been underpaid.

"This news is devastating for families already struggling to keep up with the cost of living at Christmas time," Mr Batt said.

He said the AMWU had been denied the opportunity to bargain with AP Eagers in 2018 in seeking a new Enterprise Bargaining Agreement.

The Fair Work Commission also denied the union the chance to negotiate with the company, according to Mr Batt.

In a December 17 statement, AP Eagers chief executive Martin Ward said the company apologised "unreservedly" to its employees.

"AP Eagers is committed to paying the amounts owed to past and present employees, in full and with interest, as soon as practically possible," Mr Ward said.

"We understand the importance of ensuring our employees are paid their entitlements in full and on time."