The parliamentary committee charged with oversight of Australia’s security agencies and the raft of new counter-terrorism laws imposed in recent years has suffered a major blow, with Labor veteran Anthony Byrne likely to move on.

Byrne has been the longest-serving Labor figure on the Parliamentary Joint Committee on Intelligence and Security, a committee established under the Intelligence Services Act to oversee intelligence and security agencies. He chaired the committee from 2010-13 and was deputy chair in the last term of Parliament. Crikey understands that he has declined to return to the committee, of which he would have been deputy chair in the new parliament.

The six years since 2010 have been the most important in the history of the committee, with a major expansion in the remit of the committee and its elevation to a de facto position as the vetting body for all new security legislation put forward by governments, which began when then-Attorney-General Nicola Roxon referred a raft of national security reforms to Byrne’s committee in 2011, including data retention. Byrne, a Victorian MP who keeps a low media profile, has developed a bipartisan reputation on national security and extensive contacts with US and UK counterparts, and presciently warned in early 2014 of the need for the government to put forward counter-terrorism reforms before terrorist attacks made rational debate about them more difficult (in fact, the Endeavour Hills shooting occurred in Byrne’s own electorate).

He and the now-retired Labor senator John Faulkner drove the expansion of the committee’s responsibilities and the push to transform the committee into something closer to the US/UK model, in which intelligence committees have substantially greater powers and independence to inquire into intelligence matters and oversight security agencies.

Due to Byrne’s efforts, the committee — which has a tradition of always issuing unanimous reports — now has a slate of legislative reviews to perform in coming years, will routinely receive detailed information from agencies on issues such as data retention that it can delve further into, and now oversees Australian Federal Police counter-terrorism activities as well. However, Byrne is believed to be frustrated that the goal of a genuinely independent, stronger committee that can initiate its own inquiries remains out of reach. A Labor bill to enhance the powers of the committee along the lines Faulkner and Byrne wanted perished with the previous parliament, and the Turnbull government appeared to downgrade the importance of the committee when it replaced former chair Dan Tehan — who had supported Byrne’s efforts to strengthen the committee’s role — with hard-Right former soldier and Liberal MP Andrew Nikolic.

Nikolic’s subsequent loss of his seat at the July 2 election means the Prime Minister has the opportunity to appoint a chair who can restore the committee’s standing and role, but the absence of the highly experienced Byrne will deprive it of much-needed firepower. Byrne was disliked by security agencies for his no-nonsense willingness to go after them at public hearings, and he thoroughly savaged the Attorney-General’s Department in his committee report on the Roxon reform proposals. He also spotted and headed off the Department of Immigration’s bid to retain Australians’ biometric data. Without a clear chair or co-chair and with the loss of Byrne’s expertise, a big question mark now rests over what should be the most important parliamentary committee.