An emergency beacon set off near Sumner appears to be a false alarm.

Maritime New Zealand's Rescue Coordination Centre and the Canterbury Coastguard worked together to locate the source of an unregistered ship's distress beacon that went off shortly after 3pm.

But a Maritime NZ spokeswoman says no one has been reported missing or has been found after an extensive search.

She says they've now been stood down.

Maritime NZ say beacons are sometimes sent to the dump or accidentally activated in garages.

They say this shows why it's important for boaties to register their beacons.