Police and fire crews have contained a gas leak in central Porirua, caused by a truck that collided with a gas valve this afternoon.
Police were asking people to avoid the Parumoana St area of central Porirua, near the Pak'nSave supermarket.
The area was cordoned off and traffic control was in place.
The southbound off-ramp from SH1 was closed at Porirua.
The Transport Agency was warning motorists of delays.