Banks are warning their customers in the Netherlands to beware of a new con trick in which scammers phone people posing as helpdesk workers.

Dozens of people have so far been conned out of as much as €150,000 after falling for the trick and giving crooks access to their accounts, television programme Kassa reported.

In some cases, the conmen knew how much money people had in their accounts, making them extra convincing, Kass said. This information has probably gleaned by the scammers placing software on their victim’s computer via phishing emails, allowing them to take screen shots when they make a banking transaction, fraud investigators say.

‘We were called by someone on the ING number, and a worker who told us that people were trying to steal from our account,’ one victim told the programme. ‘We had our doubts, but the woman knew things which only a bank worker would have known.’

The couple was urged to send the money to a ‘safe account’ to keep it out of the reach of hackers, but on going to their local branch the next day to recover the money, as they had been instructed by the scammers to do, they discovered all their savings had gone.

At least 119 victims have so far come forward, and have been conned out of at least €2.6m, Kassa said. According to the Dutch payments association Betaalvereningen Nederland, the number of reports about this type of con have gone up five fold since April, reaching 300 in July alone.