Officials at the Post Office have also received complaints that some wavebands have been affected by people illegally using two-way radios. The radios can be used to tamper with taxi meters.

A lengthy police investigation concluded a triad-linked syndicate might have been operating a fleet of taxis, the meters of which were fixed to inflate fares.

The arrested drivers, aged between 35 and 51, were questioned at Kowloon traffic police headquarters.

They were released on police bail last night but were ordered to report back next week.

In yesterday's operation, 14 taxis were intercepted and examined.

Ten driver are believed to have modified their meters and used two-way radios without a licence.

All but one of the taxis were returned to the drivers after the illegal radios had been disconnected.

A police source said investigating officers believed the drivers had spent substantial sums on installing devices that could at least double their daily income by speeding up the meters.

Police believe drivers have been using mobile telephones to send electronic pulses to trigger meters to run faster - a technique which is difficult to detect.

The majority of the syndicate's fleets are known to have operated at the airport and around major hotels in Tsim Sha Tsui to prey on tourists.

In January, police arrested three taxi drivers for tampering with their meters to more than double fares.

In one of the taxis, police found a device installed next to the clutch which clocked up another 90 cents every time the driver touched it with his foot.

The meters in the other two vehicles had also been tampered with.