SEOUL, KOREA - SOUTH Korean prosecutors said on Tuesday they have arrested a florist for pruning his rivals' business by clicking repeatedly on their online advertisements.

The Seoul prosecutors' office said the man surnamed Jeong was charged with breaking laws on promoting communication networks and protecting information.

Victims claim Jeong, 44, caused 500 million won (US$550,000) in losses to rival florists, the office said.

In South Korea, companies pre-pay portal operators a fee which dwindles each time an advert is clicked. When the fee is used up, the ad disappears.

Jeong is also suspected of launching so-called distributed denial-of-service attacks, in which a flood of incoming messages forces the targeted website to shut down.

Because of this, the other florists could not get what they were paying for from their advertisements.

Prosecutors said they were questioning four other florists for allegedly colluding with or funding Jeong to nobble their rivals.

South Korea, one of the world's most wired societies, has seen its online ad market grow rapidly in recent years. -- AFP