The Netherlands has instigated 30 criminal investigations into the possible export of chemicals, materials or equipment which could be used to make weapons of mass destruction (WMDs) since 2012, ministers said on Thursday.

Virtually all cases where the investigations have been completed have ‘led to a conviction’, defence minister Ank Bijleveld and foreign minister Halbe Zijlstra told parliament in a briefing, without giving further details.

The export of equipment and chemicals which can be used to make such weapons is banned under UN and EU treaties to which the Netherlands is a signatory.

The ministers were responding to MPs questions in the wake of an interview given by Onno Eichelsheim, head of the Dutch military security service MIVD, in which he said the Netherlands was ‘a supermarket’ for countries seeking to obtain technology for the development of WMDs.

Such technology and related products is particularly interesting for countries such as Iran, Pakistan, North Korea and Syria, the MIVD director said in the interview with news agency ANP last September.

That interview, the ministers said on Thursday, had been given to make Dutch companies and institutes aware of the risk, so that attempts to win expertise and materials could be headed off.

Most of the products involved were dual use – and could also have a legitimate civilian purpose, the ministers said. ‘They are subject to strict supervision and controls and have to be properly licenced for export,’ the ministers said.