Reports an apparent mass stabbing on Auckland's North Shore began at a Murrays Bay home

Emergency services have swarmed the area, with reports several people were injured in a random knife attack.

A resident says she was told by an officer her neighbour had been stabbed - before the alleged offender continued a rampage at the beach.

It's understood he then fled to Mairangi Bay.

A Montrose Cafe worker says a good samaritan brought down the attacker with a pair of crutches.

Photos show a cordoned-off area at Mairangi Bay beach with a broken crutch lying on the ground.

Police are giving an update shortly before three-pm.