Chinese intelligence agents have been pursuing an aggressive campaign of intimidation against Falun Gong followers in Australia, according to defectors and a former intelligence analyst.

"There's very good evidence that Chinese intelligence services do monitor and harass dissident communities like Falun Gong," said Paul Monk, former head of the China desk at the Defence Intelligence Organisation, one of Australia's main spy agencies.

His comments backed up the recent claims of three Chinese defectors who said Beijing targets dissidents at home and overseas.

The latest whistle-blower is a senior officer in a unit of the Chinese security service known as 610, who claims he fled to Australia after a dissident was tortured to death at the police station where he worked.

The man has been granted a protection visa which allows him to stay in Australia. Chen Yonglin , a senior diplomat at the Chinese consulate in Sydney, went public last week with claims that Beijing has a network of around 1,000 spies in Australia, monitoring pro-democracy groups and separatist movements for Tibet, Taiwan and East Turkestan.

The central government has dismissed the claims as a fabrication.

Mr Chen, 37, is now in hiding with his family while he awaits a decision on political asylum.

A second asylum seeker, Hao Fengjun, said he had worked as a state security officer in Tianjin municipality.

Dr Monk said the defectors would provide information of vital interest to Australia. "At the very minimum, Chen would be very interesting to debrief, especially given the reports we're hearing about China building up its spy network in Australia," he said.

Mr Chen was probably referring to informants and moles rather than paid-up agents when he claimed China had 1,000 spies in Australia, Dr Monk added.

"Spies can mean anything from case officers to undeclared agents and informers in the community. The number may be a little on the high side, but hundreds would not be an exaggeration," he said.

"There's no serious doubt that China has been building up its spy network. There's a considerable diaspora in Australia, and the Chinese authorities are very good at putting pressure on people."

A Falun Gong practitioner in Australia said intelligence agents had tried to recruit him as an informer on a trip back to China.

Philip Law, now an Australian citizen, said he was held for three days while visiting Beijing in 2002.

"There were about 15 plain-clothes police or national security office [personnel]. They rushed from all directions and caught me," he told ABC television.

"They asked me to spy for them. They [said], 'Once you go back to Australia, collect all the information we want and send [it] back'."

Chinese emigrant Zhang Cui Ying said agents had damaged her car on several occasions and threw a dying cat into her yard.

"I hope that the Australian government ... will clear out the spies and protect the peaceful environment for Australian people," said Ms Zhang, 42.