Reporters walked unchallenged into Chief Executive's Office at Tamar site
Security at the new Chief Executive's Office in Admiralty is under review after three reporters bypassed security checks and were allowed in without being questioned.
The three were arrested for attempted burglary after their foray on Thursday, but were released later without being charged.
The embarrassing security breach came on the day that Chief Executive Donald Tsang Yam-kuen returned from holiday and settled into his office in the new government headquarters at the Tamar site.
One of the three, Emily Tsang Oi-ying of the Ming Pao daily, said she had been 'a bit surprised' to find herself in the office after receiving a visitor's card and being allowed to walk through the building unhindered.
The chairman of the Legislative Council's security panel, James To Kun-sun, said the offices were not ready for occupation.
'Security is very loose in the complex, as many construction workers are still working there,' To said.
Police said the reporters had failed to 'produce a convincing explanation of their presence' in the office and had been taken to Central Police Station for further inquiries.
'When the trio was requested to provide details of their identities and reasons for their presence, they gave different explanations at different junctures, saying that they were public officers, visitors or they had lost their way,' police said.
Officers then reviewed video from the scene and obtained statements from security officers.
'As a result, it was believed that the trio did not have any criminal intent to burgle and they were released unconditionally after being verbally warned,' the statement said. They were released shortly after midnight.
It is not known whether Tsang was in the office at the time.
Tsang's office is on the third floor of the low block at the development. Visitors' passes should not normally allow access to the block. Security staff and police should patrol the ground floor, while Tsang's office has its own police guards.
Emily Tsang said the journalists had been given visitors' cards to enter the complex, and had not been stopped as they made their way through the building. She said a staff member leaving the Chief Executive's Office held the door open.
The journalist said she had been planning to report on the progress of decoration at the offices, and had not known what office she was entering.
'I was a bit surprised that I was actually inside the Chief Executive's Office,' said Tsang, who only realised where she was when she saw a doorplate with the name of Raymond Tam Chi-yuen, director of the Chief Executive's Office.
She walked around for about five minutes before she was questioned by a uniformed police officer.
A spokesman for the Chief Executive's Office said security would be strengthened.