More than 800 officials at the Civil Aviation Safety Authority (CASA) face the loss of three days off and another three days of personal leave entitlements in return for an unspecified pay rise.

But bosses at the air-safety agency admit that they still do not know if their package of cuts will be tough enough to satisfy the government's stringent Australian Public Service "bargaining framework".

CASA's negotiators told unions in late December that the agency had space in its budget for a pay rise but warned it would come at a price, with workers expected to trade away days off on Easter Saturday, Labor Day and their Christmas shutdown day.

The days are not mandated as public holidays in the National Employment Standards but are designated holidays in the CASA enterprise bargaining agreement.

Personal leave entitlements will be cut from 18 days to 15 under the proposal.

The authority's bosses also want to strip conditions and entitlements out of the enterprise agreement, which cannot be altered during the life of the deal, and move them to "policy", which has no such legal protection.

The move is in line with the government's instructions to strip down and simplify enterprise bargaining agreements across the service, with agency managers ordered to wage war on "duplication".

CASA wants procedures for dealing with underperformers taken out of the enterprise bargaining agreement and moved to policy, as well a requirement to hold talks with an agency employee before moving them from full-time to part-time work.

The authority also wants to be free of the requirement to consult staff and unions before changing employment policies.

The authority is waiting for approval from the Public Service Commission before it reveals fully what is on offer and put its bargaining proposal to its workforce for a vote.

But across the service, negotiations are stalled as agencies and departments battle to get the commission to sign off on proposals.

Only two agencies, the Financial Services Authority and the Employment Department, have managed to progress their negotiations to the point of a ballot of their workforces, with staff overwhelmingly rejecting pay offers of 1.3 and 1.4 per cent respectively.

A spokesman for the authority said it would not talk publicly about the talks but assured workers public holidays mandated by the Commonwealth legislation were not under threat.

"It is not appropriate for CASA to comment in detail on the enterprise agreement negotiations at this time," he said.

"Public holidays are mandated under the Fair Work Act and cannot be removed by an employer."