Hearings were expected to resume after they were postponed on Monday and Tuesday and were going to be held in the Assembly's chamber.

But Opposition Leader Elizabeth Lee said on Tuesday evening she did not know when estimates would resume.

"We're still in the dark about what's going to happen for the rest of the week," Ms Lee told Sky News.

It came as inspectors from the ACT's workplace safety watchdog were unable to find any evidence of a risk assessment undertaken for committee hearings at the Legislative Assembly.

The notice was first served to speaker Joy Burch on Friday afternoon after inspectors found the Assembly had not identified "reasonably foreseeable risks in the workplace or implemented adequate control measures" in relation to the transmission of COVID-19.

Ms Burch is considering taking legal action against WorkSafe ACT in the Supreme Court over the notice, saying it represented a "grave threat to the privileges of the Assembly".

In a letter to Work Health and Safety Commissioner Jacqueline Aguis, the speaker said the matter was of "deep constitutional significance" as it cut across the separation of powers.

"By the terms of the notice, you purport to have a power to restrain all the Assembly's select and standing committees from performing their core scrutiny and accountability functions on behalf of the Assembly, under threat of a fine for non-compliance and until actions specified by you are fulfilled to your satisfaction," Ms Burch wrote.

"Such a proposition is entirely without merit."

But a new notice was issued after Ms Burch had sent the letter. It said that inspectors had requested evidence of a risk assessment undertaken in relation to the estimate hearings from committee deputy chair Andrew Braddock and Legislative Assembly Clerk Tom Duncan.

It said that neither were able to provide evidence of an assessment, the notice also said neither could "demonstrate knowledge" of any assessment.

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The notice also said that Mr Duncan was unable to provide evidence of any risk assessment undertaken for any committee hearings. The Clerk said it was up to the committees to undertake the assessments as they were run "differently and independently".

Estimates hearings with government ministers were due to be held over a two-week period from August 15 to August 26. In the hearings, ministers face questions about the recent 2022-23 ACT budget.

The hearings were to be held face-to-face but Workplace Safety Minister Mick Gentleman had raised concerns over some officials being forced to attend in-person.

It is understood Mr Gentleman was pushing for a hybrid arrangement where ministers would attend in-person but some officials could choose to attend remotely.

An ACT government spokesman confirmed advice was sought from WorkSafe about the requirement of face-to-face hearings.

The new notice also found the estimates committee had not appropriately consulted with ministers about the hearings. Letters were sent to ministers.

"When inspectors reviewed a copy of the supplied letters, it was identified that the letters did not capture the nature of consultation in line with section 48 of the Work Health and Safety Act," the notice said.

Meanwhile, Community and Public Sector Union regional secretary Maddy Northam wrote to Mr Duncan expressing concern about the Assembly's work, health and safety requirements.

Ms Northam said it was the union's understanding that the Clerk provided advice to Ms Burch that work, health and safety functions do not take precedence over the Assembly's legislative, representative and accountability functions.

"This statement is not only deeply concerning but suggests that you consider the Assembly to be above or immune from WHS requirements that apply to every other workplace in the country," Ms Northam wrote.

"If this is indeed the view of the Assembly, then the CPSU holds serious concerns regarding your ability to effectively provide a safe and healthy workplace for workers, volunteers or visitors to the Assembly."

But Mr Duncan said he outright rejected any suggestions he did not take the health and safety of employees seriously.

In response to Ms Northam, he said that the Work Health and Safety Act did apply to the Assembly and there was a health and safety committee which was responsible for overseeing the requirements of the act.

"The committee is the primary communication channel for Assembly workers, through workplace and management representatives, regarding workplace health and safety matters," Mr Duncan wrote.

Mr Duncan said a COVID safe plan was a standing agenda item.

Deputy Chief Minister Yvette Berry was asked on Tuesday whether she felt WorkSafe had gone beyond its remit but she would not comment on the matter. She did say hearings had previously been held online and workers needed to be safe.

"We do want to make sure that everybody's safe during those committee hearings and that's the main thing," she said.

"We've been able to have those committee hearings online over the past couple of years and the government's been held to account."

Ms Berry said social distancing in the committee rooms was difficult and it was important the Assembly ensured workers were as safe as possible.

"We are still in a COVID-19 health pandemic and we still need to make sure that as an employer we are responsible for workers in our workplace, which is the Legislative Assembly," she said.

"The committee rooms are quite small enclosed areas [and] with the number of officials who attend those meetings it does mean that it's impossible to socially distance so the committee hearings have been moved to the chamber."

The ACT Legislative Assembly agreed on Monday to develop a select committee to investigate the issuing of the WorkSafe ACT notice.

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