Tax Office boss Chris Jordan says it costs 14 times more to insure his public servants against workplace injuries than their private sector counterparts.
The Commissioner of Taxation has told a Senate Estimates Committee that the high rate of psychological injury claims, particularly "adjustment disorder" among public servants was a driving force behind the ATO's $53 million premium bill last year.
But federal workplace insurer Comcare disputed the commissioner's figures and said the ATO could pay lower premiums simply by improving its performance in getting injured workers back to their desks.
Mr Jordan told a Senate Estimates Committee this week that the ATO paid 2.8 per cent of its payroll to Comcare and it compared badly with private sector professional outfits who would pay about .02 per cent.
The commissioner described the rate his agency was paying as ""quite a high multiple when compared to other organisations".
Mr Jordan is not alone in lamenting the cost of insuring his workforce; The Canberra Times revealed in March that bosses across the public service had cried foul over sharp increases in their Comcare premiums.
The heads of several agencies cash-strapped agencies had been knocked back in their pleas for reductions in their premium bills
The insurer has clawed its way back into the black after two years of horror financial results, with the recovery driven by a get-tough policy forcing public service employers to pay premiums reflecting the true cost of comp claims by their workers.
The ATO boss told the cross-party committee that he had identified psychological disorders as a factor in the Tax Office's claims profile.
"As a general proposition, there are more psychological disorders in the public sector than in the private sector," he said.
"There is what is called 'adjustment disorder', which has become a much more prevalent claim.
"They tend to be longer term and quite expensive claims for the adjustment disorder."
Employees are often diagnosed with adjustment disorder when they are not coping with a situation in the workplace.
But Comcare had little sympathy for Mr Jordan's plight on Thursday with a spokesman for the insurer saying the Tax Office's boss' fate was in his own hands.
"The Australian Taxation Office's workers' compensation premium reflects the agency's performance," the spokesman said.
"Comcare does not set premiums based on our own whims."
The insurer took issue with the commissioner's comparison with the private sector and supplied premium figures that painted a less bleak picture than Mr Jordan had presented to the committee.
"It is also misleading to compare the ATO's premium with the average for a different single industry, such as professional services," the spokesman said.
"The ATO is an agency with a mix of professions and occupations, and there is no comparable organisation in the private sector.
"ATO's premium rate for 2015-16 has reduced from 2.54 per cent to 2.31 per cent (excluding GST) of payroll, falling from $49.2 million to $42.2 million.
"This was driven by an improvement in the agency's claim incidence, and in the cost of those claims."
The Comcare spokesman added that psychological injuries accounted for 15 per cent of all claims accepted in the year to the end of March 2013, 17 per cent the following year, and 16 per cent in the year to the end of March 2015.
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