The siphon is so large it cannot contract into it's shell. Like other geoducs P. zelandica burrows downwards in the mud and extends a siphon 30-45 centimetres up to the surface of the substrate. The siphon contains two tubes. Water is sucked down one tube, filtered for food and then expelled through the other.

This species lives 20-40cm buried in the sand. It can be found around the North, South and Stewart islands and occurs mainly in shallow waters (5–25 metres) in sand and mud off sandy ocean beaches. Another geoduc species (Panopea smithae) is found in deeper New Zealand waters.

Filter feeder.

Local fishermen sometimes get large numbers in their trawl nets after a big storm.

Common Seashells of New Zealand: Parkinson