HONG KONG : Police in the southern Chinese enclave of Macau on Wednesday defended their handling of a violent May Day protest over salaries that saw one man claimed he had been hit by an officer's bullet.

The police officer's actions in firing his revolver in the air sparked further fierce clashes with protesters and was attacked by critics as heavy-handed and an affront to freedom of expression.

Officials said a man aged 50 was undergoing an operation on Wednesday afternoon after he was hit in the neck by a metal object as he rode his motorcycle some 300 metres from where the shots were fired.

Police said they had launched an investigation to see if the object, which punctured the victim's lung, was one five bullets fired by the officer to clear the crowd of more than 1,000 when the protest turned violent.

The march had been called to protest against the low wages unskilled workers are being paid at a time when a flood of overseas investment into the city's famous casino industry had produced double-digit economic growth.

Unions, which organised the May Day protest of more than 1,000 people, alleged the problem was being compounded by casinos' readiness to hire cheaper and illegal workers from China and the Philippines.

They said the police crackdown on Wednesday was part of a broader effort by authorities to suppress criticism of the Beijing-backed government of Chief Executive Edmund Ho.

"It is just another example of this incompetent government's attack on freedom of speech," said Jose Maria Pereira Coutinho, a member of Macau's legislative assembly and president of the Macau Civil Servant's Association Union.

"This is not the first time the government has restricted our right to speak out," he added.

Macau is a largely autonomous region of China which reverted from Portuguese colonial rule in 1999.

Historically closer to the communist regime of China than its neighbour Hong Kong, the city made up of a small peninsula and two islands has always been considered politically docile.

Protests in Macau are rare and political violence is almost non-existent. The last time police were brought out in force was during a rally in 2000, and before that during riots in 1967.

The city's closeness to China has prompted critics - especially those advocating more democracy - to accuse the Beijing-backed government of suppressing free speech.

Concerns have grown over the government's treatment of the media since the former government minister for transport was arrested last year following an ongoing graft investigation in the city.

Coutinho said the authorities, as a result, had become paranoid.

"They have started acting very defensively and protectively," he said.

Protest organisers voiced concern at the use of paramilitary police to quell the mob Tuesday, but Security Police chief Lei Siu-peng defended the decision to put them on the streets as an "appropriate measure".

A police statement read: "Demonstrations should be carried out in a lawful manner and pose no threats to normal social and economic activities, and to other people's lawful rights.

"The government stressed its determination to maintain the rule of law and social order, and any attempt to disrupt Macau's stable development would not be tolerated," it added. - AFP/de