Danish bank customers who use a Mac are currently unable to access the NemID online banking system. Apple’s internet browser Safari automatically blocks Java software, which the NemID system is built upon. As a result, internet banking is inaccessible to one out of every ten online banking customers in Denmark.

Jyske Bank, Nykredit and Arbejdernes Landsbank are currently investigating the matter but have so far been unable to solve the problem.

“There doesn’t seem to be any way around the problem,” a spokesperson from Arbejdernes Landsbank told Politiken newspaper. “But we’re working on it.”

Mac users first experienced difficulty accessing their NemID accounts over the weekend. It was first thought that Apple’s latest update to its operating system was to blame, but it has since been revealed that Apple has decided to block specific versions of Java.

The problem also concerns Firefox users, as that internet browser has also started to block the Java software in question.

Apple has yet to comment, nor has the software firm Oracle, which created Java.

UPDATE, FEBRUARY 6: As many commenters below have pointed out, upgrading to version 7 of Java seems to fix the issue.