EXCLUSIVE: An incredible security breach which saw a heavily-armed man walk into Australian Federal Police headquarters in Sydney and mix with unsuspecting Counter-Terrorism police has been blamed on "human error".

Seven News has revealed that a man armed with knives and a samurai sword, simply walked into the headquarters on Tuesday and mixed with unsuspecting Counter-Terrorism police.

The 22-year-old drove into the basement of the AFP headquarters located in Goulburn Street in central Sydney, after telling guards he was there for an appointment.

The man was allowed to drive into the basment car park after telling guards he had an appointment. Source: 7 News.

He wandered around the building before getting into a lift with an officer from the counter terrorism unit unchallenged.

The man was armed with knives at the time.

The pair got out together on the Counter-Terrorism floor, where the 22-year-old was finally confronted and arrested.

When police went back downy to the basement to search the man’s car they found a samurai sword.

Only yesterday, it was revealed that the Sydney Federal Police headquarters were a possible target for a terror attack allegedly planned by a 15-year-old boy and others.

While AFP would not comment on camera about the incident, they confirmed in a written statement that an investigation was underway.

“The breach of security protocols was caused by human error,” the statement said.

“As a result an investigation into the breach is underway.”

While AFP is not unaccustomed to sending out media release when they make arrests, they did not such thing over this incident.

The man already faced court two days ago and was charged with infiltrating the AFP building. Due to this, police say it would be inappropriate to make any further comments.

The lapse in security in what ought to be one of Australia's most secure buildings, comes only two months after Curtis Cheng was shot dead outside NSW police headquarters.

Only recently the NSW Government agreed to security upgrades at Sydney police stations.

“We do operate in a very different environment, we are now dealing with very real threats and risks to our own office,” police commissioner Andrew Scipione has previously said.


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