Harriet Harman has emerged as the frontrunner to take over the vacant chair of parliament’s standards watchdog, with the only other declared candidate so far being her fellow Labour MP Stella Creasy. The role is vacant after the appointment to the shadow cabinet of Chris Bryant, who used his resignation letter to express concerns that there were still too many organisations regulating MPs’ conduct. Parliamentary rules mean that the post – for which nominations have a cut-off point of 17 October – has to be from the official opposition. A ballot of all MPs will take place on 18 October if there is more than one candidate at that point. Harman, who was widely praised for her chairing of the Commons privileges committee inquiry into Boris Johnson’s Partygate statements at Westminster, used X, the new name for Twitter, on Thursday to declare that she would be putting her name forward in the contest to succeed Bryant. Known as the “mother of the house” on account of being the longest-serving female MP, Harman would be expected to continue the standards committee’s work of streamlining different codes and structures. Creasy told the Guardian that she would be speaking up for the adoption of a new approach similar to landmark recommendations aimed at overhauling the Australian federal parliament’s toxic workplace culture. “The Australian approach, where they’ve sought a much more systematic approach is a work in progress but it answers the questions many have about the role of MPs as employers and the role of staff. So many of the cases that come before the standards committee involve questions of poor management that turn into bullying and harassment,” she added. The MP for Walthamstow also said she would be “standing up” to the Independent Parliamentary Standards Authority (Ipsa), regarded as a flawed system by many MPs. Controversies have included its decision, for which it later apologised, to give MPs the go-ahead last year to charge taxpayers for their staff Christmas parties. “I have been somebody who has long been part of the debate about how we root out sexual harassment and bullying in politics and I’ve also been somebody who’s been prepared to stand up to Ipsa and say: ‘You’re getting it wrong, and you’re damaging our democracy as a result.’” Early supporters of Creasy included the Conservative MP David Davis, who told the Guardian: “I have nothing against Harriet, and indeed I have supported her in the past when she being criticised by Boris Johnson’s supporters, but I want the person who does this job to be around after the election. “I think Stella has been even-handed, she has a good record on things like combatting harassment. A part of me also prefers a non-establishment character for something like this. They have got to be be someone who doesn’t mind rocking the boat if there is an issue which requires that.” In his resignation later, Bryant paid tribute to committee members and staff, adding that he was pleased that its decisions had been upheld when they were appealed against. “Far from being a ‘kangaroo court’, every member is focused on ensuring due process and a fair hearing as the house would rightly expect,” he added, in an apparent reference to the accusation that Boris Johnson and allies had levelled at the separate privileges committee. However, he said he believed there was still signifiant room for reform, writing: “I worry that with too many organisations regulating MPs’ conduct – and with too many separate codes – there is a danger that neither members nor the public can possibly understand the gallimaufry of regulation.”