Hao Fengjun told Australian Broadcasting Corp television on Tuesday that he had worked for China's security service, known as 610, in the northern port city of Tianjin.
Hao said he travelled to Australia as a tourist in February and then applied for political asylum.
His comments came after Chen Yonglin, a 37-year-old political affairs consul at China's consulate in Sydney, sought asylum saying spies were hunting him for aiding pro-democracy groups.
Hao said he supported claims made by Chen that Beijing operated a vast spy network.
"I worked in the police office in the Security Bureau and I believe that what Mr Chen says is true," Hao told Australian Broadcasting Corp's Lateline programme.
"As far as I know, they have spies in the consulate, but they also have a network - spies they've sent out.
"Like the National Security Bureau and the Public Security Bureau in China, they send out businessmen and students to overseas countries as spies. They also infiltrate the Falun Gong and other dissident groups."
Falun Gong is an amalgam of religions, meditation and exercises that the Chinese government considers an evil cult.
"As far as I know, they (China) have spies in the consulate, but they also have a network - spies they've sent out ... they send out businessmen and students to overseas countries as spies"
Hao told Lateline he was currently in Australia on a temporary visa while he waited for his refugee application to be decided by the country's immigration department.
Chen made his bid for political asylum public on Saturday when he told a Sydney rally to mark the anniversary of the 1989 Tiananmen Square pro-democracy protests that Beijing saw him as a threat because he offered help to democracy groups and Falun Gong.
Chen, who is in hiding with his wife, Jin Ping, 38, and six-year-old daughter, has written to Australian Foreign Minister Alexander Downer asking for a rare "territorial asylum visa" and applied for a protection visa through the immigration department.
China's Ambassador to Australia, Madame Fu Ying, on Monday laughed off Chen's claims about a Chinese spy network and fears that he could be kidnapped and sent home.
Fu said Chen had no reason to be afraid about returning to China.
A spokeswoman for the Chinese embassy said on Wednesday no further comment would be made on Hao's claims.
China is accused of infiltrating
Both Hao and Chen said they would be persecuted by the Chinese government if they returned home.
"If I go back to China there's no doubt the Communist government will certainly persecute me. They know I have confidential information, some of it top secret, and I'll be severely punished," Hao said.
A spokeswoman for the US embassy said on Tuesday Chen had also contacted a US consulate in Australia about his situation, but she was unable to comment further.
Local media said Chen had asked if he could defect to the US.