The Ombudsman audited 52 businesses in Phillip, Weston, Woden, Holder and Queanbeyan after a high number of requests for help from young workers in these suburbs.

"While the national average of requests for assistance from young workers was around 24 per cent, in Woden the figure was 35 per cent and in Queanbeyan 44 per cent," Fair Work Ombudsman Natalie James said.

"We know that young workers can be vulnerable in the workplace due to a lack of awareness of workplace rights and limited work experience.

"These figures prompted us to take a closer look to ensure that businesses in the region were meeting their workplace obligations. Unfortunately close to a third of the businesses we audited were not."

Of the 52 businesses audited, 83 per cent paid their employees correctly, 79 per cent complied with pay slip and record-keeping requirements and 69 per cent complied with all requirements.

However the Ombudsman issued two formal cautions and two compliance notices.

Five businesses breached workplace laws around pay slips and record keeping while five had breaches relating to pay rates.

Four businesses had both pay rate and pay slip breaches.

The Ombudsman recovered $27,054 from four businesses on behalf of 28 employees.

In one matter, a small restaurant was slapped with a compliance notice after the Ombudsman found three workers had been underpaid $7826.

Two workers, one full-time and one part-time, were on salary but their base hourly rates were lower than the award.

The other was employed as a casual, but only received $19.83 an hour, significantly lower than the award.

The restaurant also failed to keep a record of all their hours worked, a legal requirement for all casual employees and employees covered by the salaried provision of the award.

The money has now been paid back.

A large electrical-construction company with more than 90 staff was found to have underpaid 22 workers a combined total of $18,711.17 over five months.

The discrepancy was picked up in a sample of records for 15 employees, which revealed a casual level-one electrical worker was underpaid $1.85 an hour.

The business was hit with a formal caution.

The Ombudsman found businesses that were larger or part of an industry organisation were more likely to comply with workplace laws.

Businesses with more than 15 staff had a compliance rate of 89 per cent, while those with fewer than 14 employees had a compliance rate of 65 per cent.

Those in industry groups had a compliance rate of 88 er cent, while those who weren't had a rate of 60 per cent.

Businesses found to have breached workplace laws will be monitored closely by the Ombudsman.

But in December, the Ombudsman found two in five ACT businesses who were given a second chance fell short of their workplace obligations.

"As a result of the earlier campaign the agency initiated litigation against two businesses for record-keeping breaches, with penalties of more than $56,800 handed down against a cafe operator in one of the matters," a spokesman said.

"The second matter remains before the court."

For help, visit fairwork.gov.au or call the Fair Work Infoline on 13 13 94.