A rescue helicopter from Nelson and another from Wellington were used to take two of the moderately-injured casualties to hospital - one to Wairau Hospital in Blenheim, the other to Nelson Hospital. The third was taken by road to Wairau Hospital.
The man with minor injuries travelled by sea in a Coastguard boat to Picton, and from there to Wairau Hospital by road.
Nelson Marlborough Rescue Helicopter pilot Stuart Farquhar said a railing around a large deck had given way.