Police say investment fraud cases in Hong Kong have jumped by over 50 percent for the first four months of the year, when compared to the same period last year.

They said victims as young as 14 and up to 86 years old lost a total of HK$786 million.

They said the largest individual loss was HK$27 million.

They said they've noted a surge in cases involving both cryptocurrency and stock-related investment scams.

Billy Ng, senior Inspector with the Commercial Crime Unit, said scammers often use fake trading apps to trick people.

"Scammers often use mobile applications to carry out fraud," he said.

"The method is usually for scammers to first pose on online social platforms, discussion forums or send messages to instant messaging apps, attracting victims to invest with 'low risk and high returns'. However, most of these investments do not exist or are full of traps," Ng said.

Ng said some scammers created fake trading records to lure victims, and fabricated false transaction records in the victim's online account to make it seem that the assets are growing.

But when victims tried to cash out, the scammer would delay payments and they would eventually realise they had been duped, Ng said.