This follows the discovery of an unspent shotgun cartridge in the public gallery by parliamentary staff a fortnight ago.
The Vanuatu Police Force is investigating the incident.
At the same time security measures have been stepped up at parliament.
The acting clerk of parliament, Leon Teter, said the incident underscores the urgent need for security to be beefed up in the house during parliament's sittings.
Mr Teter said visitors to the public gallery will now have to go through security screening, including magnometers and metal detectors.