Russia-linked ships sail unchecked through Dutch waters despite international concerns about spying and sabotage, reports the Volkskrant.

Dutch MPs agreed in a motion in January to “actively police” infrastructure in the North Sea by stopping and searching ships that sail within 393 kilometres from the coast because of the risk to vital infrastructure and potential for oil leaks.

But the Volkskrant says that the Russian “shadow fleet” – around 1,000 tankers that transport Russian oil to countries such as India and China but fly under another flag to avoid sanctions – is not checked.

In July, Germany and Sweden increased checks on foreign ships. Earlier in August, Norway said that it would ask all foreign ships sailing through its exclusive economic zone to show insurance papers. Britain, Denmark, Estonia and Finland already have extensive procedures.

Finland has accused a sanctioned tanker linked to Russia of damaging important undersea cables, and this month charged the captain and two senior officers with aggravated criminal mischief and interference with communications.

However, the Volkskrant reports that not a single ship in Dutch waters has been investigated since MPs adopted the new rule.

The Dutch infrastructure ministry told the paper that it believes there are legal restrictions around searches, that it uses information from other countries and is researching other measures.

Critics are not convinced. “We have a government that, on the one hand, recognizes that our security is at risk due to Russian hybrid warfare and that the shadow fleet continues to fill the Russian war chest,” D66 MP Jan Paternotte, who jointly put forward the motion, told the Volkskrant. “On the other hand, the government has been investigating for eight months whether we can carry out checks.”