In an ugly debate in the Assembly chamber on Thursday, MLAs from both major parties accused each other of ''extreme'' behaviour while debating a motion brought forward by Attorney-General Simon Corbell.

Mr Corbell tabled the motion to ban the Assembly from being affiliated with religious services after Speaker Vicki Dunne's controversial church service on Monday.

In an hour-long debate, the government accused the Speaker of dividing the Assembly, while Liberal MLAs attacked Mr Corbell's motion as ''discriminatory''.

The opposition also claimed the government's proposal could have ''unintended consequences'' for the Assembly chamber prayer or moment of reflection, Ramadan dinners, smoking ceremonies, public holidays and even Christmas trees.

Chief Minister Katy Gallagher accused the opposition of ''running interference'' by claiming the ''sky would fall in'' and said the motion was simply to make the Assembly's position as a secular institution clear.

The motion, carried nine votes to eight, will prevent the Assembly and the Speaker's office from being formally associated with religious ceremonies but will not ban members from holding or attending such functions in their capacity as MLAs.

Mr Corbell told the Assembly Mrs Dunne should have withdrawn from Monday's church service because of the controversy it caused.

''This is about making clear that we do not want you, as the Speaker, to go and organise ceremonies and events that draw a link between this place and any religious or philosophical belief,'' he said.

The Attorney-General said the government was not trying to prevent MLAs from professing their religious faith publicly in the Assembly or in the community.

''It is not about saying that members cannot organise a service or religious ceremony which they believe is appropriate for the conduct of their business as members,'' he said.

''What we are suggesting, Madam Speaker, is that it is not appropriate for you, as the Speaker, to profess to organise, or lend the authority of your office, to a ceremony which is designed to draw a clear link between the authority of your office, the Assembly and a religious ceremony.''

New Opposition Leader Jeremy Hanson said the government risked ''turning the multi-faith community of the ACT into a political football'' and that the proposal was ''discrimination''.

The opposition also asked if the Attorney-General's motion would prevent Assembly members from taking part in activities organised by religious groups in the Canberra community or stop those groups from holding functions at the Assembly.

Canberra Liberals deputy leader Alistair Coe said the government was trying to ''stifle freedom'' and was ''anti-faith''.

''What does it mean for the Assembly hosting or supporting religious events such as Diwali, Ramadan, Christmas parties, carols by candlelight, Christmas trees and others?'' he said.

But the government accused the opposition of ''hysteria'' and said the motion made it clear such activities would not be affected.