Federal police charge IT worker, 24, with attacking government website and say he has claimed to be a leader of hacker group

Australian police have arrested a man they say is affiliated with the international hacking collective LulzSec on a charge of attacking and defacing a government website.

The 24-year-old senior IT worker, whose name was not released, was arrested on Tuesday night at his Sydney office, the Australian Federal Police said. The man, who police say has claimed to be a high-level member of the hacking group, was charged with two counts of unauthorised modification of data to cause impairmen, and one count of unauthorised access to, or modification of, restricted data. If convicted he could face up to 12 years in jail.

Lulz Security, or LulzSec, is an offshoot of the hacking group Anonymous. LulzSec was formed in 2011 and quickly grabbed headlines after claiming responsibility for a series of high-profile cyberattacks against the CIA, Sony Pictures, the US Public Broadcasting Service and Britain's Serious Organised Crime Agency.

Several members of the group have been arrested, including its reputed leader, known as Sabu. Sabu turned out to be FBI informant Hector Xavier Monsegur, who federal officials said helped them build a case against several other hackers. Two weeks ago British LulzSec hacker Ryan Ackroyd pleaded guilty to several cyberattacks.

Australian Federal Police Superintendent Brad Marden said the man arrested on Tuesday hacked into an Australian government website and defaced it earlier this month. Marden would not say which website was attacked, only that it did not belong to a federal agency. Police did not believe any sensitive data was accessed in the attack or that anyone else was involved.

The man, from Gosford, about 50 miles (80km) north of Sydney, claimed to be the Australian leader of LulzSec, Australian Federal Police Commander Glen McEwen said. But Anonymous Australia appeared to laugh off those claims on Twitter. In response to a follower asking if anyone knew who the man was, the group tweeted: "Nope not part of the usual suspects on any of our [channels] of communication."

Police began investigating the man two weeks ago after they discovered the government website had been hacked.

"This individual was operating from a position of trust who had access to sensitive information from clients including government agencies," McEwen said. "The AFP believes this man's skill sets and access to this type of information presented a considerable risk for Australian society."

The man was released on bail and ordered to appear in court next month.