Former Major General Paween Pongsirin arrived in Melbourne a few days ago on a tourist visa and said he planned to seek political refuge, according to the Australian Broadcasting Corp.
"There must be some place, some safe place for me," he said in an interview with the broadcaster. "I came here because Australia is a safe place."
Paween quit the police in November, saying an order to transfer him to Thailand's south would expose him to revenge by members of trafficking syndicates still at large.
National police chief Jakthip Chaijinda said at the time Paween could have asked for protection but chose to resign instead.
"We issued 153 warrants across all areas and that included government officials ... I had to do just my duty, not to think of danger or trouble, but now I realise how dangerous it was," Paween said.
Thai police will investigate Paween's case but have not been informed of any threats to him, Thai police spokesman Dejnarong Suthicharnbancha said.
"Paween should have sent a complaint to his supervisor for investigation," Dejnarong told Reuters on Thursday.
Thailand has indicted 88 people suspected of involvement in human trafficking since opening a nationwide investigation into gangs after the discovery in May of 30 bodies buried in graves near the Thailand-Malaysian border, which prompted an international outcry.
"He was brought in as a hard-nosed experienced investigator, someone who has a reputation for being incorruptible," Phil Robertson of Human Rights Watch Asia told the ABC. "He now feels it is no longer safe to stay in Thailand."
Australian government officials were not immediately available to comment on whether Paween had applied for asylum.
