One in 10 voters cast their ballot by proxy at the local elections earlier this month, and in some polling stations the figure is almost one in three, according to research by broadcaster NOS.

Last week, the mayor of Gorinchem brought in the police because of concerns that people were being forced to hand over their votes, and on Monday evening, local officials will decide if there should be a new election.

“You never know what circumstances led someone to hand over their voting card, or if the person voting on your behalf is actually voting as you want them to,” John Bijl from election advisory institute Perikles told the broadcaster. “It will always remain a weakness in our voting system.”

Observers from the OECD have issued warnings about the overuse of proxy voting in the Netherlands in the past. They say it conflicts with the principle of “one person, one vote”. In other countries which allow proxy voting, the rules are stricter, NOS said.

Officially, people in the Netherlands are allowed to vote by proxy if they are not in a position to do so themselves, but in practice many people let someone else vote for them because it is easy.

There are also wide regional variations in the Netherlands. In Groningen, 7% of votes are cast by proxy, but on the former island of Urk, which is staunchly fundamentalist Protestant, the figure is one in five.

And in the Sam Sam community centre in The Hague, 450 people voted, but over 700 votes were cast because of proxy voting, an analysis of this year’s voting figures showed.

The biggest percentages for proxy voting are in “Christian communities such as Urk and Volendam, and in areas with a large number of people with foreign roots,” the OECD said in a 2017 report on the basis of statistics collected by the Kiesraad election council.

The Hague city council did not respond to NOS’s questions.