The independent auditor's report noted that the government is anticipating stress on the diesel market after Russian oil is banned from European ports on Dec. 5 as part of a sixth package of sanctions levied on Moscow following its invasion of Ukraine.

"A shortage of diesel might arise due to the upcoming sanctions against Russia," a summary of the 60-page report said. "At this moment there is no national crisis plan for oil prepared, as there is for gas and electricity."

The report noted that crucial parts of the economy such as the trucks that supply grocery stores run on diesel, but in case of a physical shortage, it is not clear which users would have priority.

A spokesperson for the Court of Audit said the report was intended as a factual observation, not as a criticism of policy.

Energy Minister Rob Jetten, in response to the report, said his ministry has begun working on an oil crisis plan, but that individual players and organizations in the sector already have "playbooks".

Russian oil accounted for about 35% of Dutch imports in 2021, and major refineries in Rotterdam have been customised to make diesel from heavy Russian crude.

The Netherlands Petroleum Stockpiling Agency (COVA) has a strategic reserve of oil holding about 90 days of national consumption, in line with international obligations.

However tapping those reserves, as happened twice this year, has only a temporary effect.

"It is, according to COVA and the Ministry of Economic Affairs, very much in question whether Dutch refineries are capable of obtaining enough heavy raw oil to satisfy continental European diesel demand," after Dec. 5, the audit report said.

(Reporting by Toby Sterling; Editing by Jan Harvey)