The threat from extreme rightwing terrorism in Australia has increased in recent years and will remain an “enduring threat”, according to Australia’s spy agency.

The Australian Security and Intelligence Organisation issued the warning in its latest annual report, adding that “extreme rightwing groups in Australia are more cohesive and organised than they have been in previous years”.

The comments amp up the agency’s concern about rightwing extremist terrorism, after Asio boss Duncan Lewis told Senate estimates in April it was an important issue but the Christchurch massacre had not changed the agency’s calculus.

The massacre of 49 people at two mosques in Christchurch, for which 28-year-old Australian Brenton Tarrant has been charged, prompted renewed scrutiny of the far right including by Australia’s home affairs department.

The Asio report said the national terrorism threat level remained at “probable” because “credible intelligence … indicates an intention and capability to conduct a terrorist attack in Australia”.

“The principal source of the terrorist threat remains Sunni Islamist extremism and emanates primarily from small groups and individuals inspired, directed or encouraged by extremist groups overseas,” it said.

The report argued that Isis had reduced ability to direct external attack planning due to “sustained losses” but warned the group “continues to inspire attacks globally – including against the west”.

The Asio report linked the threat in Australia to the global context, where terrorist attacks are “now an indelible feature of the security environment”.

“Terrorists inspired by violent Islamist extremist and rightwing extremist ideologies reinforce their respective narratives by fomenting hatred and inciting violence to realise their ideological objectives,” it said.

“The rightwing extremist attacks in Christchurch on 15 March 2019 demonstrate that it takes only a single individual to embrace and act on a violent extremist ideology to have a global impact.”

Asio concluded “the threat from the extreme rightwing in Australia has increased in recent years”.

“Extreme rightwing groups in Australia are more cohesive and organised than they have been over previous years, and will remain an enduring threat.

“Any future extreme rightwing-inspired attack in Australia would most likely be low capability and conducted by a lone actor or small group, although a sophisticated weapons attack is possible.”

The Asio report noted that violent protests in Australia were rare and community cohesion was high but “over the next 12 months, acts of opportunistic violence or civil disobedience at protests are possible, particularly those attended by counter-protesters”.

The report said since September 2014 there had been seven terrorist attacks in Australia and 16 “major counter-terrorism disruptions”.

Concern about the far-right in Australia has increased due to attempts to infiltrate mainstream political parties and mobilisation of white supremacists before the federal election.

Australia’s tough gun laws are widely credited with helping to avoid devastating consequences of politically-motivated violence such as the Christchurch massacre, the murder of UK MP Jo Cox or the massacre of 77 people by rightwing extremist Anders Breivik in Norway.