Spotless has held the public housing contract since 2005, looking after 10,600 homes, housing almost 6 per cent of Canberra's population. Over five years, the fee paid to Spotless ($6.9 million in the most recent year), and the maintenance bills are expected to total $242 million, Auditor-General Maxine Cooper reported on Thursday.

But Dr Cooper found that oversight of Spotless is "inadequate".

Dr Cooper said about $42 million a year was spent on public housing maintenance and repairs, on the basis of work orders issued by Spotless. Spotless is supposed to follow up on 5 per cent of work orders each month to check the work, and is paid incentives or charged abatements as a result.

But Dr Cooper said it was not clear those audits were being done properly. A check in November 2013 found that 85 per cent of the 21 tenants supposedly audited had not received a visit or phone call from Spotless, with no documentation or photos of the 21 audits. Spotless found no fails, whereas a departmental team found that 19 of the 21 work orders had either trade or administrative deficiencies.

In late 2013 and early 2014, 100 work orders were checked by the government, finding a 19 per cent fail rate compared with Spotless' fail rate of 3 per cent. Only a quarter of tenants had received a call from Spotless about the work and only 15 per cent had received a visit.

The Audit Office itself found its own failings when it looked at work order checks over three months last year, with 60 per cent not using the correct template, and even when templates were used many didn't include the tenant's name or or signature, the date and time, or answers to questions about sub‐contractor behaviour, work completion and satisfaction.

While the contract with Spotless said the checks on work should be done in the homes, Spotless had been allowed to do the checks by telephone.

The auditor also found failings in Spotless' employment of target groups, with the company supposed to employ 10 Indigenous people, 30 tenants, 43 people with a disability and 25 young people. Most of the targets were not met, except the youth target, which was well exceeded, despite the issue being raised repeatedly between the department and Spotless.

She found that Spotless had met targets for urgent but not routine maintenance. And she raised questions abut the reliability of the timeliness information.

In 2015, Spotless did its own audit of 111 work orders that went to one of its sub-contractors. It found 86 per cent of the work orders had defects as a result of "communication errors, incorrect or no documentation and inconsistency of completion dates between a work order and data entered". The time taken was wrongly stated, mostly by a day, but in one case "the discrepancy of several weeks seemed designed to record an elapsed time just within the target".

The government should look more deeply into the reporting of work times "to assure itself that the problems identified … are not experienced more generally, and that Spotless staff and sub‐contractors are undertaking the correct processes for the completion of work orders and for data entry", she said.

She also pointed to the potential conflict of interest in Spotless overseeing maintenance that was done by its own in-house group, called Asset Services.

In 2014‐2015, Asset Services was given 1888 work orders, worth $1.1 million.

"Independent quality assurance of the work undertaken by Asset Services would provide assurance that this arrangement is delivering value for money for the territory," she said.

She found the method of controlling costs for each maintenance job was sound, with sub-contractors bidding for jobs based on a list of standard rates.