China has encountered a rising Internet security problem over the past three years mainly triggered by a growing number of profit-driven computer virus writers, hackers and illegal traders.

Despite the public security agencies' escalating actions against online theft and fraud, anti-virus professionals said the situation is not "entirely optimistic".

They believed the turning point could come with the introduction of legislation on cyber crime and the protection of virtual property.

According to the latest survey conducted by the Ministry of Public Security, 65.7 percent of the 15,000 companies polled had suffered Internet security problems from May last year to May this year, 11.7 percentage points higher than the previous period.

The problems include computer viruses, worms and Trojans, junk mail, port scanning, Internet attacks and webpage manipulation.

It also indicates that 91.4 percent of computers, the highest ratio recorded since the annual survey started in 2001, were attacked by viruses compared with 74 percent for the previous period, and 87.9 percent for the period, May 2004 to May 2005.

"The number of spyware and Trojans, which aim to hijack users' accounts and passwords, have increased markedly, and computer viruses have been widely spread, which have directly affected Internet users," the ministry said on Wednesday.

While stepping up its efforts in launching an information security rating system to diversify protection, the ministry will also promote public education and establish a channel for netizens to report viruses and seek help.

It also vows to deal more sternly with illegal online activities.

Leading anti-virus companies in China said they also recorded the spread of extremely active viruses, and expressed concern about rampant illegal online activities.

"Our company hijacked about 134,000 viruses in the first half of this year, up 12 percent from a year ago. We have seen an explosive growth in viruses that maliciously steal accounts and virtual properties," Shi Yu, an anti-virus engineer with Beijing Rising International Software, told China Daily Thursday.

An underground business chain, from virus writers, hijackers, traders and buyers of banking information or virtual properties has taken shape, he said.

Fu Sheng, a general manager with the anti-virus department of Qihoo, said: "The profit is huge. Selling a bug sometimes can make several million yuan, and the risks are very low."