Mrs Dunne, Liberal, says about 100 letters were sent. "All stamps were paid for privately by me. I personally prepared and produced the letter, but the incorrect stationery was inadvertently used," she said in a short statement.

She was responding to inquiries about a letter she wrote to pre-selectors on April 14. She used parliamentary letterhead and envelopes for the letter, which set out her case for the votes of Liberal pre-selectors in Ginninderra.

The parliamentary guide for members says the resources and facilities of the Assembly "are not provided to assist members with election campaigning, other party-political activities or private purposes".

"Any use of those resources and facilities for purposes beyond the electoral and parliamentary responsibilities of MLAs could lead to a member vacating office," the guide says.

"It is also the case that such misuse would offend relevant provisions of the Members' code of conduct."

Any allegations a parliamentarian has breached the code of conduct are dealt with by standards commissioner Ken Crispin if there is a complaint.

Mrs Dunne's letter came as she prepared to travel to London in April for a meeting of the Commonwealth Parliamentary Association, missing most of the Liberal preselection but returning in time for the Ginninderra vote on Monday this week.

Mrs Dunne, a member of the ACT parliament for 15 years, is the Liberals' longest serving member other than Brendan Smyth. Before being elected, she was on the staff of Gary Humphries.

This year, the move to five electorates has seen her home suburb, the Belconnen suburb of Evatt, become part of the new Gungahlin electorate. Mrs Dunne will continue to represent Ginninderra so the shift leaves her living just outside the borders of her electorate.

Mrs Dunne told preselectors she and the party had decided she should run in Ginninderra as "the only sitting member among the line-up there".

Her letter hints at the confidence the Liberals are feeling in the run-up to the 2016 election, where they believe they have a real chance at winning.

"The next election, with new boundaries and an expanded Assembly, will I believe be a game-changer," Mrs Dunne wrote.

"It presents great opportunities for Jeremy Hanson and the Liberal team, who will continue to roll out solid policies and campaign strongly over coming months, in contrast to the increasingly disorganised, disheartened and discredited Barr government."

Mrs Dunne also promoted her parliamentary colleague Alistair Coe for "masterful" work on transport that "may well prove decisive in winning us this election".

"In a town like Canberra, with its government-centred workforce and with the local media being what they are, it's never easy for the Liberals to win government. It takes a perfect storm, with everything going right for us - and a few things going wrong for Labor, federally as well as locally. We're not there yet, but I believe we're well on track," she wrote.