It was agreed that this question is not well documented in the Law of the Sea Convention. Nevertheless, some delegates had divergent views on the extent of port State jurisdiction in terms of high seas fisheries. There was also disagreement on the customary international law in this respect. Some delegates advocated an extended jurisdiction for the port State, based on the coastal State's special interests. Others argued that port State's authority was the exception rather than the rule and is limited to a number of specific cases, such as the protection of the marine environment and the prevention of pollution. The amount of data that a vessel needs to provide the port State upon calling in might be dependent on its activity.
Port State jurisdiction might be exercised at the discretion of the port State or at the request of the flag State. This is particularly relevant in the case of open registries whose vessels rarely stop in their national waters. Other nations expressed their fear that this policing action on the part of the port State might lead to discrimination. This concern led to proposals that guidelines be established to limit the detention powers of the port State. In addition, it was agreed that a degree of proportionality had to be maintained between the suspected offense and the enforcement measures the port State might take.