Currently, law-enforcement agencies are not required to obtain a warrant to wiretap individuals in an investigation. But this is in violation of the Basic Law, two judges ruled in recent Independent Commission Against Corruption cases.

In one case, a District Court judge ordered a stay of proceedings against the defendants because the ICAC breached legal professional privilege by wiretapping a conversation between lawyers and a defendant.

Secretary for Security Ambrose Lee said Monday the executive order on covert surveillance, delivered by Chief Executive Donald Tsang last Friday, was in line with the constitution and did not impinge upon individuals' human rights.

He defended covert surveillance, saying it is a necessary practice for law-enforcement agencies around the world.

``Even in highly democratic countries, they conduct covert surveillance. The Hong Kong Police Force and the ICAC are no exceptions,'' Lee said.

Because local courts have always accepted evidence gathered through covert surveillance, Lee said ceasing the practice would seriously affect the ability of law-enforcement agencies to carry out their duties. ``The practice has successfully brought criminals or corrupt officials to justice in the past,'' Lee said.

``Should this practice be brought to a halt, only a minority group of people will benefit - that is, corrupt individuals or criminals.''

Although some legal experts have expressed worries that the executive order will provide a shortcut for law-enforcement agencies to conduct covert surveillance on individuals without legal liability, Lee said the interim measure offered clearer legal backing for law-enforcement officers.

``But it did not authorize any additional power to law-enforcement agencies ... creating any new criminal liabilities on any individuals, or removing any freedoms and rights that [were] enjoyed by the local public under current laws,'' he said.

Lee stressed the government will consult various sectors before enacting the legislation.

Legco's Security Panel will also host a special meeting next Monday to discuss the executive order. Lee will attend the session to explain the government's position.

Tsang's executive order came in response to a series of court cases thrown out by judges, who ruled that law-enforcement agencies had overstepped their legal bounds.

That initiated a Security Bureau review last month, which examined covert surveillance guidelines.

The executive order now gives officers the authority to approve surveillance.

The number of such officers will be designated at a later stage. At present, there are about 200 officers in the police, customs, immigration and ICAC who could authorize wiretapping. The ICAC itself has 10 such officers.

Barrister-legislator Ronny Tong restated Monday the executive order lacked any legal foundation and urged the government to scrap it.

Tong said it should be court judges - and not the authorized police, customs, immigration or ICAC officers - responsible for approving urgent covert surveillance applications from law-enforcement agencies.

``We have more than 100 court judges to share the duties 24 hours a day to approve urgent applications,'' Tong said.

The Standard, citing sources reported Monday that Tsang's aim to issue the order was to salvage the morale and reputation of the ICAC.