The tax office may not be able to carry out its duties properly in the coming years because so many officials have left in the ongoing reorganisation, a union official has warned.

Erik Rutten of the senior civil service union VHMF has warned MPs that the number of tax office staff may drop from 30,000 to 23,000, thousands more than ministers had forecast.

This will pressure performance and may encourage people to start fiddling their taxes, Rutten said in a written warning to MPs.

The union is calling on the government and MPs not to let the workforce shrink to below 26,500.

In October, junior finance minister Eric Wiebes placed the tax office under direct ministerial control and replaced the organisation’s board with a senior civil servant reporting directly to him.

The shake-up came after Wiebes was heavily criticized for his measures to encourage voluntary redundancy within the tax service, which were seriously oversubscribed. That has led to a €70m shortfall in the budget set aside to pay for the reorganisation.