Core extension policy
ICA sets three non-negotiable starting rules
ICA's current Extension of Entry Permits page says extension applications must be lodged well in advance of the expiry of the current Entry Permit. It also states that extensions are issued only to people currently in Papua New Guinea and cannot be granted while a person is outside the country.
ICA further states that there is no period of grace in relation to extensions. That means a traveller should not wait for the existing permit to expire and assume they can regularise the stay afterwards through a routine extension.