The Dutch tax office is owed €168m by people who no longer live in the Netherlands and were wrongly paid some form of social security benefit, the finance ministry confirmed on Friday.

Most of the cash is owed by people who have moved back to Belgium, Germany and Poland. The total has been mounting up since 2006 when the new benefit system was introduced, the tax office report shows.

In total, more than 100,000 people living in 189 countries owe money. Not all the cases involve deliberate fraud, the tax office said.

The benefits were paid to low income households and covered housing, healthcare and childcare. The payments were made automatically and only assessed at the end of the year.

Efforts are now being made to claw back the payments made to people in the top three countries. They will be contacted by mail about their debt and there will be a pilot involving local debt collection agencies.

However, junior finance minister Eric Wiebes has admitted it will not be easy to reclaim the money, the Telegraaf reports.