Greens MLA Shane Rattenbury at the ACT Legislative Assembly during question time.

Greens MLA Shane Rattenbury will not attend a church service organised by Vicki Dunne. Photo: Jeffrey Chan

Balance-of-power MLA Shane Rattenbury says Canberra Liberal Vicki Dunne is taking the role of Speaker backwards with her plans for a Christian commencement service for the ACT Legislative Assembly.

The Greens minister and former speaker said Mrs Dunne was reverting to old parliamentary practices with the service, which will mark the beginning of the new Assembly year despite not having the support of most MLAs.

The ceremony has proved controversial, with Chief Minister Katy Gallagher and now Mr Rattenbury making it clear that they will not attend it.

But Mrs Dunne, who told the Assembly in November that she would be "a modern Speaker", said on Wednesday that the February 11 ceremony was an "innovation" for the territory.

Mr Rattenbury echoed the criticism of Ms Gallagher and said he did not support ''institutionalising a religious ceremony into the proceedings of the Assembly".

Mr Rattenbury, who supported Mrs Dunne's election to the Speaker's chair, said the service did not align with the Liberals MLA's plans to be a modern Speaker.

"This is not a modernising of the Speaker's role," he said.

"This is quite the contrary.

"This is quite contrary to the approach the Assembly has taken.

"She's certainly reverting to an older style or older practice of parliaments that the Assembly has previously eschewed."

But Mrs Dunne dismissed Mr Rattenbury's criticism.

She also sent a letter to MLAs on Wednesday reminding them of the official order of preference in speeches, which dictates that the Speaker is the fifth dignitary to be acknowledged, ahead of ACT government ministers.

The Speaker said on Wednesday that the ceremony was an "innovation" because it had never been tried by the Assembly.

"My response is that the Assembly has never reached out to the community through faith," she said.

"I see the Speaker's role as reaching out to the community through all stations and connecting to the community.

"We have gone quite out of our

way to make sure this is open to all religious groups."

Mrs Dunne also said that she had not insisted that the Chief Minister, Mr Rattenbury or any other MLAs attend and whether they participated or not was "a matter for them".

"The thing I'm concerned about is that there seems to be a move by the Labor Party to prevent their members from participating," she said.

"The impression I have is that caucus has been instructed not to go."

Ms Gallagher said Labor MLAs had not been instructed not to attend. "From my understanding of the meeting we had with Labor Party members, no one indicated that they were going, but I certainly haven't told people that they can't go," she said.

"If an individual Labor member wanted to attend the service that's a different thing to having the Assembly authorise this service and create that formal link that, once established, would be almost impossible to break."