Initial results from the extra border controls the Dutch have been undertaking for the past three months show give a mixed picture, but are nevertheless encouraging, immigration minister Marjolein Faber told MPs on Friday.

During the three months to March 9, 250 people were refused entry to the Netherlands, and 90 people were arrested for involvement in crimes such as human trafficking or drug offences, the minister said in a briefing.

A further 30 people applied for asylum, one of whom was sent back to the EU country where they had first applied. In total, 41,750 people and 9,900 vehicles were checked.

In the same period 2023/24, 260 people were arrested, a far greater number than this year. A further 100 people applied for asylum on being stopped, also far more than this year.

However, fewer people – 150 – were turned back at the border for not having the right papers to go to the Netherlands. Fewer people and vehicles were also singled out for the extra checks.

Immigration minister Marjolein Faber said the results do differ “significantly” from a year ago, but it is difficult to determine the exact reason. Fewer people may have been arrested because 45% fewer refugees are coming to the Netherlands, she said.

Despite the downturn in arrests, Faber said the results are “all in all encouraging” and were achieved within existing budgets without causing traffic jams, as had been feared.

The project will now continue for a further three months, she said. In the intervening period, talks will continue with other ministers about extending the controls again.

The police unions, however, are unimpressed by the results, with NPB chairman Nine Kooiman saying that the minister had removed capacity from other border control departments to carry out her extra checks, “creating a problem on the investigative side”.

Ramon Meijerink, acting chairman of the ACP union, pointed out that there are 840 border crossings between the Netherlands and Germany and Belgium.

“It is a real shame that border checks are being framed in this way,” he told the AD. “Border controls are there for our security and involve so much more than just this.”