Snapped at Tauranga today.

Snapped at Tauranga today was this Piper PA-31-350 Navajo Chieftain ZK-NSP (c/n 31-7552069) with a small bulge below.

Is this a small cargo pod or ? 

It was listed with Search and Rescue Services Ltd of Taupo on 15-10-2009 after having served with Air Nelson from 1987 until its Taupo move in about December of 1992 for Helicopter Leasing NZ Ltd followed by Helicopter Services (BOP) Ltd from 27-02-2001.
Photo from Grayson Ottaway.
Also on site was a noisy grey Seasprite.