Australia’s national security legislation watchdog has called for more transparency from the country’s intelligence agencies, warning “unnecessary secrecy” is against the public interest and could fuel “malicious” fake news.

In his annual report to parliament, the independent national security legislation monitor, James Renwick, has called for as much information as possible to be published about the exercise of powers under Australia’s national security laws.

“It cannot be emphasised too strongly how important it is that all that can be published about the exercise of such powers, consistently with the public interest, should be, and regularly, and not as it were as a favour but as a matter of duty by the executive government, owed to the other branches of government and to civil society,” Renwick says.

“One often overlooked reason for publishing information is to prevent or correct error and to forestall mischievous speculation. In a world where malicious actors propound ‘fake news’, unnecessary secrecy can be seriously counter-productive.”

Renwick gives the example of the United Kingdom routinely publishing statistics that show the number of counter-terrorism arrests, convictions and acquittals and details of the sentences, and says Australia should follow suit.

“There is simply no good reason not to do it, it would encourage public confidence and it is something which should be repeated more widely.”

He calls for commonwealth agencies to publish annual statistics concerning the counter-terrorism threat, including the number of terrorism arrests; the number of convictions for terrorist offences including the offences and sentences; the length of terrorism trials; the number of prisoners currently incarcerated for terrorism offences; and an approximate annual average of the number of persons under investigation for counter-terrorism activity.

Renwick suggests the data should also be provided separately for children.

“I anticipate that all of this information may be made public,” he says, adding that classified information could still be provided on a confidential basis to various oversight agencies.

Another of the INSLM’s key recommendations is for the government to amend the Intelligence Services Act to create a legal obligation to ensure that classified annual reports of the Asis and Australian Signals Directorate are provided to the leader of the opposition, with parts not tabled in the parliament to be treated as secret. He says this is the requirement for Asio, but is not mirrored across all agencies.

“In making decisions about what government information should be made public, it should go without saying that official discomfort is an insufficient reason for secrecy or suppression,” Renwick says.

He points to a judgement from 1980 in which the commonwealth sought to prevent publication of some official information, which stated that “it can scarcely be a relevant detriment to the government that publication of material concerning its actions will merely expose it to public discussion and criticism.”

Renwick flags that he will be making further recommendations to ensure regular and open reporting about the exercise of national security and counter-terrorism powers, and “highlighting the benefits for public trust in so doing”.

The monitor’s annual report for 2018-19 said that Australia’s terrorism threat continued to come mainly from radical and violent Islamist action, but Renwick also warned that there were “increasing concerns about radical, violent, rightwing activity”.

Renwick says that in the case of the extreme rightwing, a “diffuse” narrative centred on the belief that white races were being replaced by non-whites with the connivance of elites that encourage immigration.

“The narrative is also a mix of illiberal ideas, anti-capitalism, neo-Nazism and nativism often with an overlay of personal grievances and an apocalyptic worldview,” Renwick says.

“The advocated response is violence directed at both groups to reverse this trend and to achieve ‘racial purity’.”

“The current resurgence of extreme rightwing violence will also require special scrutiny to prevent its expansion.”

Last week, the head of Asio, Mike Burgess, warned in a speech on Australia’s security threats that far-right extremism was a growing problem.

The home affairs minister, Peter Dutton, followed the speech by calling for “leftwing lunatics” to also be dealt with, claiming that this included Islamist terrorist groups.

Renwick says the credible threat of one or more terrorist attacks will remain a significant factor in the Australian national security and counter-terrorism landscape for the “reasonably foreseeable future”, but warns the threat continues to evolve.

“It would appear that at least some counter-terrorism laws will be necessary for many years to come. Of course, that conclusion does not provide carte blanche under the INSLM Act for any particular statute, because the questions concerning the necessity of each particular law, its proportionality and its protection of individual rights must still be asked and answered.”