Japan's Parliament has passed a controversial law on telephone wire tapping despite widespread objections from opposition parties and human rights activists.

The upper house voted by a large majority in favour of the bill, but only after opposition politicians had used every possible procedure to block it.

After their no-confidence motion against Prime Minister Keizo Obuchi failed, they used filibustering tactics, such as what the Japanese call the "ox walk".

Members walked excruciatingly slowly to the ballot box to cast their votes in an effort to overrun the allotted time.

Despite staying up all night, it was all to no avail.

Japan's police have now been given the authority to tap telephones in the investigation of crimes involving:

• drugs
• guns
• murders committed by groups
• the smuggling of illegal immigrants into Japan.

The government has said wire tapping will better equip the police to tackle organised crime.

Doomsday cult

It is also expected that the law will be used against such groups as the Aum Shinri Kyo "Doomsday" cult, which released nerve gas on the Tokyo underground train system in 1995, killing 12 and injuring thousands more.

The legislation requires that an independent witness, such as an employee of the telephone company, be present during the wire tapping and that those whose phone calls have been monitored are notified after the event.

But left-leaning politicians fear the new law will give the police too much power.

They are anxious that wire taps will be used against leftists and other critics of the government.