Changes to the calculation of rates for units and apartments that came into effect last year were referred to the Public Accounts Committee for investigation in February, after thousands of owners and landlords signed a petition calling for the new methodology to be scrapped.

However the inquiry was nearly derailed last month, after Labor backbencher Bec Cody alleged the Liberals tried to corrupt the process by filtering submissions via a party-owned website.

It later emerged not all of the submissions made via haveyoursay.net.au were automatically forwarded on to the committee as the Liberals initially claimed, with 19 submissions caught in an outgoing spam filter.

The issue was referred to a privileges committee, chaired by Greens leader Shane Rattenbury.

The rates inquiry was supposed to continue while the privileges committee investigated the possible breach of parliamentary privilege.

The committee had been due to report on Thursday, however Public Accounts committee chair Vicki Dunne asked for an extension until September, saying the initial timeframe had been "ambitious" due to several other inquiries holding hearings this month.

"We are proposing to report by last sitting day in September but have internally resolved to try and report before then, if granted permission to report out of sessions," Mrs Dunne said.

Ms Cody accused the Liberal members of the inquiry, Mrs Dunne and Alistair Coe, of failing to make themselves available for meetings, revealing the committee had not met for five weeks and had not yet discussed the 19 outstanding submissions.

She said this was somewhat ironic as the Liberal party had accused her of trying to delay the rates inquiry by arguing for a privileges committee to be set up.

"I find it very difficult to stand in this place, and have to stand in this place, to argue about the fact we are having to extend the reporting date for an inquiry that we were told by the leader of the Opposition we were trying to stop, but we could not meet to do the important work," Ms Cody said.

Mrs Dunne admitted she had been away for three weeks on a combination of leave and official business with the Commonwealth Parliamentary Association, of which she is treasurer.

"At one stage I did get a message asking if I was prepared to phone in but it was 2am in London and I'd had a full day and had another full day and I declined to phone in," Mrs Dunne said.

Mr Coe said the committee's usual meeting day was a Wednesday, and that sitting weeks and Anzac Day had disrupted their routine.

He described the debate in the Assembly as a "storm in a tea cup" over "line and length committee activities".

"Members regularly can't attend the plethora of  committee meetings that MLAs have to attend," Mr Coe said.

"It's a bit rich for Labor MLAs to say attendance at all committee meetings is compulsory because simply going through the public hearings let alone the private meetings of the public accounts committee will show Labor members are regularly absent."

Mr Rattenbury also asked the parliament on Thursday to allow the privileges committee to report back on the conduct of the Liberals out-of-session.