Convicted match-fixer Wilson Raj Perumal says limiting online betting only to matches in the world's top leagues would help cut down on fixing because those games are not as easy to manipulate.

Perumal, now living in Hungary, presented the local edition of his book "Kelong Kings," which details his exploits and shows "to what extent football and football betting are corrupt."

The Singapore native, whose testimony has also helped convict several of his former associates in his homeland, says he does not feel any "imminent threat" to his life.

Perumal is also the key witness for the prosecution in a Hungarian trial involving 12 defendants, including Tan Seet Eng, a Singaporean also known as Dan Tan, the alleged head of a crime syndicate suspected of rigging matches around the world.