China reported more than 400,000 telecom fraud cases last year, up more than 30 percent from 2013 while causing economic losses worth 10.7 billion yuan ($1.72 billion) to unsuspecting victims, according to the latest data from the Ministry of Public Security.

Many local public security authorities say the numbers could be at least double that if unreported cases and aborted scams are included, China Youth Daily reported on Thursday.

Phone scams are common in China. The Economic Information Daily reported that the criminal investigation department of the Ministry of Public Security intercepted 24 million scam phone calls within five months while carrying out investigations into a major case.

In 2013, 75.96 million phone numbers were marked by users as scam calls, according to Qihoo 360.

Chen Weicai, a Chinese National Congress deputy, says telecom scams are mainly carried out by criminal rings based on the mainland and Taiwan.

Crimes committed by mainland-based rings involve relatively low amounts of money and are easier to crack and with losses easier to recover, while Taiwan-based scam rings often corrupt phone numbers and pretend to be police, procuratorial and judicial officers to swindle mainland victims, Chen says.

An individual scam case orchestrated in Taiwan usually involves more than 100 000 yuan, Chen claims, adding that Taiwanese criminals collect 90 percent of all corrupt money generated from telecom scams reported in the country.

According to Taiwan police, nearly 100,000 residents on the island make a living from phone scams targeting unsuspecting mainlanders.

Some local police authorities attribute the frequent occurrence of telecom scams to the low cost of committing the crime, as less than five percent of telecom scam cases are cracked nationally and less than five percent of lost money recovered.

According to the Ministry of Public Security, more than 8 billion yuan is swindled out of mainland victims and collected in Taiwan each year, while only 127,000 yuan of that has been recovered over the years.

Police say supervision and crackdowns on telecom scamming, as well as efforts to raise public awareness, have lagged behind the development of a criminal's ability to commit fraud in the past 12 years.

Experts advise mobile phone users to better guard against scams and urge telecom industry regulators to improve supervision on telecom carriers and regulate their business in a timely manner.