More than 6,300 people fell prey to "fake friend" scams in Singapore last year and collectively lost an equivalent of nearly $16 million, according to police.

Such scams involve contacting victims, pretending to be someone they know, and asking for financial assistance.

The wealthy city-state has been hit with a surge in scams in recent years, with authorities issuing frequent warnings to the public against fresh schemes from criminals.

Police said in a statement Tuesday the scams had cost victims Sg$21.1 million ($15.7 million) in losses between January and November last year.

In the latest case, five Malaysians were extradited on Tuesday to Singapore over "fake friend" scam calls involving over $1 million in lost funds, police said in a statement.

Malaysian and Singaporean police had raided two apartments in Malaysia's Johor state, which borders the city-state, earlier this month in a joint operation.

They arrested the five men between the ages of 19 and 36 for suspected involvement in scams targeting Singaporeans.

The men were extradited to Singapore on Tuesday and will be charged for conspiracy to cheat on Wednesday, police said.

Police believe the syndicate to be responsible for over 500 police reports and losses amounting to over Sg$1.4 million since June of last year.

The five men face up to 10 years in jail and a fine if convicted of conspiracy to cheat.

"The Singapore Police Force has been working closely with the Royal Malaysia Police to detect and cripple these transnational scam syndicates who prey on our citizens," said David Chew, director of the force's Commercial Affairs Department.