The head of the immigration service IND has urged asylum minister Marjolein Faber to hold off with plans to introduce a two-tier system for incoming refugees until new European rules have been implemented.

Rhodia Maas warned MPs that officials were likely to be overstretched if Faber’s plans were not streamlined with the European Commission’s pact on asylum and migration, which comes into force next June.

The PVV minister wants to create two classes of refugee, an “A status” for people who face persecution in their own country and a “B status” for those who are fleeing war, natural disaster or other circumstances.

A similar system was abandoned in 2000 because of the high number of legal cases brought by asylum seekers who wanted to upgrade their B status. Under Faber’s plan “class B” refugees would have fewer rights, including a ban on family reunifications, and less chance of being granted residency.

Maas told a roundtable consultation in parliament that experience showed around three-quarters of refugees who were placed in the lower class lodged appeals.

The IND currently has capacity to process 30,000 asylum applications a year and a backlog of 50,000, she said.

Simultaneously the service is having to implement the EU rules, which are designed to tighten external border controls while distributing refugees fairly around European member states. Each country will have to accept a minimum number of asylum seekers and have to pay €20,000 per person if they fail to meet it.

Maas urged MPs to “let the introduction of the two-status system dovetail with the implementation of the pact.”

But PVV party leader Geert Wilders, who made introducing the “strictest asylum policy ever” the top priority of the right-wing cabinet, said in a social media post that he would not tolerate any further delay to the plans.

He dismissed the IND’s objections as “obstructionism”, adding: “This is all taking far too long and we need to do much more and at great speed!”