Watch: Hackers rattle Samsung with claims of fooling S8's iris scanner

"A high-resolution picture from the internet is sufficient to capture an iris," CCC spokesman Dirk Engling said, adding: "Ironically, we got the best results with laser printers made by Samsung."

A Samsung spokeswoman said it was aware of the report and was investigating.

The iris scanning technology was "developed through rigorous testing", the firm said in a statement as it sought to reassure customers.

"If there is a potential vulnerability or the advent of a new method that challenges our efforts to ensure security at any time, we will respond as quickly as possible to resolve the issue."

Samsung's hopes of competing against archrival Apple's iPhone had been pinned on the Galaxy S8 after last year's Note 7 disaster.

The recall debacle cost Samsung billions of dollars in lost profits and hammered its global credibility, forcing it to apologise to consumers and postpone the S8 launch.

But since it was released in April it has received positive reviews and strong orders.

The CCC previously demonstrated a way to defeat Apple's TouchID fingerprint sensors -- using graphite powder, a laser etching machine and wood glue -- just weeks after the first iPhone 5s hit the shelves.

Traditional PIN protection was "a safer approach than using body features for authentication", Engling said.