Security could be ramped up at major sporting events such as the NRL and AFL grand finals amid increasing terrorism concerns.

Security at major sporting events such as the NRL and AFL grand finals and the upcoming Asian Cup of football is set to be ramped up amid growing fears they could be targeted by terrorists.

The nation’s terror threat level has been under review, and could be raised later on Thursday, as authorities become increasingly concerned about the risk posed by Australians fighting with extremist groups such as Islamic State in Syria and Iraq.

Outgoing ASIO chief David Irvine has said the spy organisation is actively considering raising Australia’s terror threat level from medium to high – which stipulates a terrorist attack hasn’t necessarily been identified, but is considered likely.

Attorney-General George Brandis said on Thursday that raising the national alert level would mean a much greater presence of police at major events such as the AFL grand final in Melbourne later this month and at the NRL grand final in Sydney in October.

“If the level were to be raised then one would expect there to be additional measures, additional policing at events where there are large numbers of the public gathered for example,” Senator Brandis told ABC radio.

Security would also be beefed up for the Asian Cup football tournament, which opens in Melbourne on January 15 when Australia plays Kuwait.

The tournament will also be played in Sydney, Newcastle, Canberra and Brisbane.

The major international event is expected to attract 45,000 visitors from overseas, and involves 16 teams including Iraq, Palestine, Iran and Saudi Arabia.

Earlier this year, Islamic State reportedly issued a threat of terror attacks at the 2022 Qatar World Cup unless FIFA moved it to a different country.

In a letter purported to be from Islamic State and published on a jihadist website and in an Egyptian newspaper, the group warned football constituted a deviation from Islam.

The letter, addressed to FIFA president Sepp Blatter, said Islamic State “has long-range scud missiles that can easily reach Qatar”.

In 2002, it was revealed that the al-Qaeda linked terror group Jemaah Islamiah had planned to attack the 2000 Olympics in Sydney but decided against it.

The plan, according to South-East Asian intelligence officials, was the brainchild of the then operations chief for JI, Riduan Isamuddin, known as Hambali, but rejected by the group’s Australian leader.

Hambali later played a major role in planning the 2002 Bali bombings, which killed 202 people. including 88 Australians, before his arrest and incarceration at Guantanamo Bay.

About 60 Australians are fighting in Iraq and Syria with groups like Islamic State, while another 100 are providing support from Australia.