Security company TrustGo Mobile noted a “dramatic increase” in the number of apps it categorises as “high risk”, which can put user personal data at risk – even if these apps do not have a malicious intent.

According to the company, there was a 43.2 percent increase in high-risk apps from the third quarter of 2012 to the fourth, with the total reaching 511,043.

This means that more than 20 percent of apps available worldwide have code which can compromise users’ personal data, make payments and promote other apps, for example.

TrustGo said that China-based stores remain the most risky, with 39.2 percent of titles categorised as malicious, high risk, or low risk/noisy (the latter category includes apps which have “the potential to annoy users with excessive notifications or advertisements).

Within China, the Anzhi marketplace was named as the “riskiest” among the major stores, with more than three-quarters of all apps representing some risk to users.

Consumers in India have the most high-risk apps on their device – three – compared with an average of 2.4 in China.

The safest app market place was Europe’s Aproov, with only 2 percent of its listed apps failing to achieve a certified rating.

Games are the most common category in which to find high-risk apps. Worldwide, more than 178,000 titles in this category have a high-risk security rating, representing 44.5 percent of the total.

TrustGo’s study covers 2.27 million apps found on 187 marketplaces worldwide during October to December 2012. It said that these serve an estimated 700 million smartphone users.