Public Service Minister Eric Abetz produced the figures in Parliament as he renewed his attack on the main public service union, the CPSU, and its approach to the present round of enterprise bargaining talks in the Commonwealth bureaucracy.

The union is taking an aggressive approach to a ballot of 1800 workers at Employment for a new pay deal, hoping to strike a blow in Senator Abetz's own department against the government's hard-line public sector bargaining policy.

A union bulletin to its members at Employment urges them to reject the minister's "dud deal" that offers 1.4 per cent over three years in return for more job cuts, a longer working day and the loss of other entitlements.

But the minister produced figures to Senate question time on Monday showing that median public-service pay rises since 2004 had totalled nearly 42 per cent while the headline inflation rate for the same period was 28 per cent.

Senator Abetz poured scorn on the union's 4 per cent across-the-board wage claim for 160,000 federal public servants, accusing the CPSU of scaremongering over the crucial issue of public service superannuation.

"The Community and Public Sector Union has been falsely claiming that the government is stripping public servants' rights and conditions," Senator Abetz told the upper house.

"This is incorrect. The CPSU claims that the government wants to cut public servants' super when the contribution rate is actually set by the trustee, a legislative instrument subject to parliamentary scrutiny.

"This is just scaremongering by the CPSU - and what's more, public servants know it.

"The CPSU should cease its scaremongering and posturing and help it members negotiate what small productivity-backed increases are possible, given the mess left by the former Labor government.

"The CPSU should also remind its members that over the last decade, median public-service pay rises outstripped CPI by 14 per cent."

CPSU National Secretary Nadine Flood, who is adamant that the superannuation guarantee is under threat, was also on the offensive, urging her members at Senator Abetz's Employment Department to reject the proffered wage deal.

"Attacking the CPSU in the Senate is frankly a bizarre way for a Cabinet Minister to conduct industrial relations policy with his Commonwealth workforce," she said on Monday. "Instead of attacking the CPSU the Minister should be talking with us."

"We have always said that we are happy to sit down with the Minister to sort out this mess he has created but 8 months after delivering Government's bargaining policy he is still refusing to meet with us. But no, rather than talk with us about a sensible solution he has again taken up the megaphone attack."

"The Prime Minister has declared that he has listened to the Defence community on ADF conditions, so why can't Minister Abetz? It's his policy that has launched an attack on public servants' conditions and pay; it is his policy that is pushing workers ever closer to industrial action and yet all he can do is fling insults. It's a bizarre way to behave."

The union leader said Employment staff were particularly alarmed by their department's plan to cut 46 jobs over the life of the agreement to help pay for the wage offer.

The ballot opens on Tuesday, December 10, and closes three days later.