More than 350 terracotta pots, some weighing up to half a tonne, have gone missing from Parliament House, and other publicly owned assets may also have gone walkabout.

The whereabouts of the pots which, according to testimony given at parliamentary estimates committees, would have needed a forklift truck to move, are unknown.

An example of the pot plants in question.

Under questioning from Labor's veteran inquisitor John Faulkner on Monday morning, Department of Parliamentary Services Secretary Carol Mills conceded that a 2013 audit, prompted by Senator Faulkner's previous inquiries, had identified that of an expected 1303 terracotta pots, just 942 could be located.