But the unions too have had to cope with some disunity, a University of NSW study has found, as both sides in the public service's epic industrial conflict succumb to "bargaining fatigue".

The university's researchers conducted interviews with four senior public servants and a union official, after guaranteeing their anonymity, to get inside what they dubbed the industrial "forcing strategy" launched by the Abbott government in 2014.

The conversations revealed friction between government departments and its key workplace enforcer, the Australian Public Service Commission, during the public service's industrial disputes which now look set to rumble into their third year.

The Commission did not respond to requests for comment on the study.

The three-strong academic team has documented the increasingly bitter conflict between Abbott-Turnbull employment ministers and public sector unions trying to resist the government's attempts to transform the workplace relations landscape of the service.

But the Fair Work Act, legislated in 2009 by the Rudd government, also emerged as key to the government's inability to enforce its will on much of its workforce, with the legislation protecting a big role for unions in the bargaining process.

The limits of union effectiveness have also been exposed, with the CPSU unable to prevent the effective freezing of the wages of much of the public service for at least 18 months.

The team, led by UniNSW workplace expert Sue Williamson says the forcing strategy aimed "to limit pay increases and improvements to working conditions, increase labour flexibility, enhance management's ability to ratchet up performance standards and enable management to gain increased power over trade unions."

"The Coalition believed that public service employment conditions should be brought into line with those of private sector employers, 'deprivileging' the Commonwealth public sector workforce," the study says.

"The Coalition attempted to use its power resources, principally the 2014 and 2015 APS Bargaining Policies, to implement its forcing strategy."

But determined resistance by a well-organised union movement, adept at using the provisions of the Fair Work Act, as well as "conflict" between employing departments and the APSC itself has mean the strategy has not gone to plan, the academics found.

"The FW Act did protect union recognition and constrained efforts by agency managements to minimise union participation in APS bargaining.

"Such protections weakened the feasibility of the Coalition government's forcing strategy.

"The practical effect of the legislation in the APS was an increased capacity and role for unions in bargaining."

The approach of forcing agencies productivity savings and cuts to employment conditions to fund any pay increases "created internal differences within the ranks of both management and unions" the research found.

"Tensions emerged between agency management and the APSC over the latter's strict interpretation of the Coalition's Bargaining Policy," the study says.

"On the whole, agency managements would have preferred increased discretion to negotiate with union representatives at workplace level."

The study reveals a picture of industrial stalemate with two sides who are each unable of achieving their ultimate goals or of completely thwarting the plans of the opposing camp.

"Even though the government maintained that participation in industrial action was low, the swathe of agreements rejected – some more than once – highlighted the effectiveness of a strong union campaign," the authors conclude.

"It also highlights the importance of legislation supportive of collective bargaining and union participation in collective negotiations.

"Nonetheless, the Coalition and its managerial agents have succeeded in freezing APS wages for the vast majority of APS employees."