An association representing Japan’s brokerages is considering tightening security guidelines for member firms, as a surge in phishing scams hits retail broking at Nomura and other houses, people familiar with the matter said.

A working group of the Japan Securities Dealers Association is discussing a revision to the current set of recommendations in order to prevent fraud in online transactions, the people said, asking not to be identified because the matter isn’t public. The body will likely go through matters including the need to more strongly urge members to adopt a thorough client verification procedure known as multi-factor authentication, they said.

A spokesperson for the association said it is largely the case that such steps are being taken, though declined to elaborate on details.

The move underlines the spreading concern around the sharp rise in unauthorized trades at some of Japan’s largest brokerages. Earlier this week, Nomura’s flagship domestic brokerage unit suspended online purchase orders for some local stocks to limit damage from the scams. The country’s regulator has also called on the industry to swiftly come up with measures and take actions against these new kinds of fraud.

The association is also discussing actions securities firms should ask their customers to take to protect themselves, since their cooperation can be crucial to block fraudulent activity, the people said. It will also look into how companies can quickly inform clients about fraud when it occurs, they said.