Fifa is concerned for the lives of players approached by match-fixers, warning that they could pay the "ultimate price".
It claims governments should be wary of the presence of criminal organisations in fixing and the "staggering" sums of money involved.
Chris Eaton, head of security at Fifa, said: "We are very concerned about the safety of players [and] officials.
"There is anecdotal evidence that some players have been killed."
He added: "Match-fixing is all about stealing money. It destroys the lives and careers of many people. Governments should be interested because the amount of money is truly staggering.
"What are those criminal organisations doing? They are spending it on other criminal activities. They use money for power and power escalation.
"Unfortunately, because of the very nature, they can very quickly accumulate a large amount of money."
Fifa, football's governing body, will open a hotline for whistleblowers in February and offer a temporary amnesty for players who admit to fixing and give evidence.
Nearly 50 players were arrested last year in connection with the worst scandal to hit the 28-year-old South Korean K-League, prompting government threats of a shutdown.
The former coach of South Korean club Sangmu Phoenix was found dead in October in an apparent suicide, three months after being charged as part of the probe.
"We have evidence of players in South Korea committing suicide because of the shame of match-fixing," said Eaton. "There are players who pay the ultimate price for resisting or for the shame of match-fixing.
"That's why its incumbent on Fifa and global society to limit access of criminals to it. We certainly have information in some parts of the world... of threats to players who have come forward.
"Most are indicating they are under some form of threat. Often these players are under the control of a senior player, or captain, or technical coach, and these are the people we need to support."
Eaton said he does not envisage any danger to Italian second division defender Simone Farina because of the player's high profile.
Farina has been paraded by Fifa as an example after he refused a 200,000 euro (£165,000) offer to fix an Italian Cup match between Cesena and his club Gubbio last November.
"He displayed model behaviour for young players," said Eaton. "He resisted significant money to fix what many players would consider an unimportant fixture."