Here's what you missed on the fourth day of Senate estimates

This is what you've missed from Thursday's hearings.

There was plenty said about embattled consultant firm PricewaterhouseCoopers today.

The Finance Department has told the firm to prevent any staff who knew about the treasury tax leaks from working on any existing or future government contracts, until an internal review of the scandal has been completed.

The Treasury Department referred the firm to the cops after its international tax boss allegedly shared privileged government information to its clients.

Meanwhile, Labor senator Deborah O'Neill wants PwC to name all of the people whose identities were redacted in emails that the Tax Practitioners Board tabled in Parliament on May 2.

Greens senator Barbara Pocock has also questioned why the Department of Finance won't ask for the names of all involved in the tax breach matter.

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Australian Federal Police deputy commissioner Ian McCartney has confirmed it will no longer be using Chinese-made DJI drones.

Upon being asked by Liberal senator James Paterson whether it was still using DJI drones for operations, Mr McCartney said it was "transitioning" from the technology.

Questions have been raised over a mystery meeting that took place between Administrative Appeals Tribunal Registrar Michael Hawkins and Attorney General Mark Dreyfus, just five days before former AAT President Justice Fiona Meagher resigned from her post.

Liberal senator Michaelia Cash asked a lot of questions about the circumstances surrounding Justice Meagher's resignation, including whether she had been pressured to resign by Attorney-General Mark Dreyfus.

But things got more interesting when Ms Cash asked about two meetings held on November 25 at the Attorney General's office in Sydney. The first meeting was with Justice Meagher, the second with Mr Hawkins

When Ms Cash asked him what the meeting was about, he said he didn't think he could talk about it because Mr Dreyfus had said the meeting was "cabinet-in-confidence and confidential, and that [he] wasn't authorised to speak about it with anyone".

When asked directly, Mr Hawkins did confirm that Justice Meagher's resignation was not discussed in the meeting.

Public Service Minister Katy Gallagher has been asked about the government's APS reform work.

"We hope that the support that we've locked in behind APS reform, the investments that are going into departments, the security of that funding so that departments know what they're getting and know that they're getting that on an ongoing sense, will give the public service the room to basically rebalance," she said.

"There will always be a need for some external service providers, external arrangements, but it's out of control, it's been out of control and we are trying to reign that back in.

Things got pretty heated in the Finance and Public Administration hearing when Liberal senator Jane Hume was questioning the Office for Women about aged care policy changes.

The opposition claimed a new requirement for all aged care centres to have a registered nurse on-site 24/7 (from July), is causing centres to close because of staffing pressures.

Senator Hume wanted to know if a gender impact analysis was undertaken "on the effect of potential closures of aged care homes".

"There isn't a measure about that for a start," Senator Katy Gallagher responded.

When the Australian Federal Police made their estimates appearance, Liberal senator James Paterson asked about why officers booted out anti-Chinese Communist Party activist Drew Pavlou from Parliament House.

The AFP has already apologised to Mr Pavlou, who was there to meet Senator Paterson and Labor MP Peter Khalil but was kicked out while he was eating lunch at the building's public café.

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