A WA cleaning company has repaid close to $450,000 owed to staff not properly compensated for their work.

An external audit found Delron Cleaning Pty Ltd had underpaid 1174 cleaners a total of $447,717 between March 2015 and March 2017.

Individual underpayments ranged from one cent to $12,100 for a cleaner in Perth.

All underpaid workers have since been back-paid.

Delron, which provides services in Perth, regional WA and Sydney, prompted the audit after it identified errors in its payroll system.

PwC was commissioned to look into entitlements owed to 1188 current and former employees across that period and uncovered the shortfall.

Underpayments related to overtime and shift work penalties, as well as part time and broken shift allowances.

Record keeping breaches relating to Delron’s casual and part-time employees were also identified.

The Fair Work Ombudsman said Delron had worked cooperatively to rectify the breaches, including signing an Enforceable Undertaking which commits staff to further training on its workplace obligations.

It will also need to complete three external audits over the next 18 months to ensure it is above board and send apology letters to affected workers.

Fair Work Ombudsman Sandra Parker said the Undertaking contained strong measures.

“We know that cleaners can be some of the most vulnerable workers in Australia and the sector remains an ongoing focus for the agency,” she said.

Delron was sought for comment.