Revellers in Australia are urged not to be terrified after counter-terrorism squad arrested a man at Sydney airport for allegedly making threats to carry out attacks during New Year's Eve celebrations, police said on Friday (30 December).

The 40-year-old man was arrested on Thursday after he disembarked a flight from London. He was accused of posting threats in an online blog, which were spotted by members of the public who alerted the police. Initial investigations suggest that it was an isolated incident and police say that they are confident there are no specific threats to New Year's Eve celebrations.

According to Acting Deputy Commissioner Frank Mennilli, the man posted on social media "a number of threats of some possible activity that he could be undertaking." Mennilli refused to give further details as the matter was before courts.

"He has been charged with a crimes act offence, not a terrorist offence," ABC news quoted him as saying. "The matter is still under investigation and there may be some further charges, but I can certainly assure everyone there is no current threat from that individual or any other person." The man is said to have no links to any cultural group.

The man is thought to have not applied for a bail and he is due to reappear in the court on 10 January.

Documents and computer hard drives were seized after police raided a house and a storage facility in Sydney.

The arrest comes a week after authorities in Melbourne said they foiled a "significant" terror plot, reportedly an Islamic State-inspired one, targeting Christmas Day celebrations in the city.

More than one million people are expected to take part in the giant annual New Year's Eve fireworks party on a harbour side in Sydney.

"We are confident that there are no current or specific threats to New Year's Eve and, while we ask people to remain vigilant, people should enjoy the celebrations," Deputy Commissioner Catherine Burn said in a statement. "The community should be also reassured that we will take swift action to ensure the ongoing safety of the public."

Australia foiled Christmas day attack
Police walk towards a door as they searched a house in the Melbourne suburb of Meadow Heights, Australia on 23 December, as part of counter-terrorism operation AAP/Julian Smith/via Reuters