A third of Australian workers are still being ripped off on their superannuation entitlements, as rogue employers pocket almost $6 billion to fatten up their cash flows, according to a new report.

Key points: Analysis of ATO figures shows nearly 3 million workers were short-changed on super

Analysis of ATO figures shows nearly 3 million workers were short-changed on super The average underpayment for those short-changed was $2,070 per annum

The average underpayment for those short-changed was $2,070 per annum The Government recently introduced potential criminal penalties for employers who fail to meet super obligations

Research commissioned by Industry Super Australia (ISA) based on Australian Tax Office data from 2016/17 has found 2.85 million workers were short-changed, with an average underpayment of $2,070 per year or $80 per fortnightly pay.

In addition, the report found 370,000 Australians who make a salary sacrifice to supposedly boost their retirement nest eggs have lost $1.5 billion as their bosses either knowingly or unwittingly counted this towards the mandatory 9.5 per cent compulsory superannuation contribution.

ISA chief executive Bernie Deane told the ABC's AM program the continuing underpayment of superannuation to workers in the face of a federal government crackdown was "a wakeup call for both major parties".

"Dodgy employers are getting a free run here. There's virtually no enforcement and the penalties for doing the wrong thing are woefully inadequate," Mr Deane said.

"The ATO has been pretty soft on this crime.

"It's a classic moral hazard where the worst thing that can happen to a boss that does the wrong thing is that they actually have to pay back the money that they should have paid in the first place and it is daylight robbery.

"Unless we see action from the major parties this election, those dodgy employers are going to continue to take advantage of lax tax laws, a weak regulator and insufficient penalties for ripping off hardworking Australians."

The gap in super savings is most acute for workers under 25 on wages below $30,000, according to the report, with those who are not underpaid accumulating 81 per cent more than those who are ripped off.

Tougher laws yet to have their full impact

The dodgy employer behaviour, described by ISA as an "unpaid super epidemic" defies action by then-financial services minister Kelly O'Dwyer in 2017, who ordered the Australian Tax Office to crack down on a loophole used by unscrupulous employers to boost their cash flows by holding back payments for four months.

"It's not right for employers to be unscrupulous in using this loophole and reducing the amount that they're paying to their employees as part of their superannuation guarantee obligations," Ms O'Dwyer said at the time.

The study by former Treasury official Phil Gallagher found, despite Ms O'Dwyer's anger at the super rip-off, the number of short-changed workers had climbed by 90,000 to 2.85 million and the unlawful proceeds to employers jumped by $340 million to $5.94 billion.

Industries most at risk include machinery operators, drivers, labourers, apprentices, technicians and community workers.

The Senate Economics Committee held public hearings into superannuation underpayment. Its final report in 2017 found, "The negative impacts of the non-payment of the superannuation guarantee are pervasive".

"The committee is particularly concerned that the individuals most at risk … often come from the most vulnerable groups in Australian society."

In a statement to the ABC, the Tax Office said employers have an obligation to come forward when they are late in paying the superannuation guarantee or do not pay it at all.

"We take non-compliance of superannuation guarantee obligations seriously and actively promote employees to report a non-payment," an ATO spokesperson said.

The ATO said, in 2017-18, more than 24,000 employers were contacted, and about $850 million was raised in superannuation liabilities, including penalties from 16,000 employers.

New legislation came into effect last month giving the ATO new powers to pursue criminal prosecutions if employers fail to meet their superannuation obligations.