Viktor Orban, prime minister of Hungary | Sean Gallup/Getty Images 5 ways the EU could send a message to Viktor Orbán How to solve a problem like the Hungarian prime minister?

The Hungarian prime minister has been a thorn in Europe's side for years and patience in Brussels is wearing thin. This week the European Commission warned Viktor Orbán that it was considering opening infringement procedures against his government, which could result in heavy fines.

Among the bones of contention are a new education bill that critics say is designed to close down the Central European University backed by U.S. financier George Soros, Orbán’s refusal to take part in the legally binding EU refugee relocation scheme, the distribution of a government survey entitled “Let’s stop Brussels!” and a campaign against foreign-funded NGOs. It's also just introduced an asylum law that includes automatic detention for all asylum seekers.

They are just the most recent examples of Hungary straying from the EU line: there are 66 pending infringement against Hungary, several of which involve cases of alleged discrimination against non-Hungarians.

So far, Brussels has been unable to lay a glove on Orbán and Frans Timmermans, the Commission's first vice president, was cautious about taking further steps, saying Wednesday that “we have to be on a very firm legal ground before we start infringement procedures.” Actions taken so far have been mainly on technical issues: but this time the protection of Article 2 of the EU treaties — on core of EU values — is at stake, Timmermans said.

The moment of truth for Orbán could come as early as April 29 at a meeting of the center-right European People's Party of which Orbán is a member — as are Commission President Jean-Claude Juncker and German Chancellor Angela Merkel. Juncker told fellow commissioners on Wednesday that "it's time to speak about the truth."

Here are five things that EU could do to send a message to Orbán.

1. Kick Fidesz out of the EPP

Orbán's strongest link to Brussels is his Fidesz party's membership of the European People's Party. According to the EPP's statutes, suspending or excluding a party would need to be approved by the political assembly of the EPP at the request of either the party's president — Frenchman Joseph Daul — or by seven party members from five different countries. But it's not in the EPP's interests to kick out the Hungarians. The EPP has 216 seats in the Parliament — making it the biggest group, ahead of the Socialists and Democrats on 189 — and losing the 12 Fidesz MEPs would shrink its lead. Plus, Hungarian MEPs are seen as loyal and hard working.

2. Ramp up the infringements

One obvious target for the EU would be to take action over Hungary's refusal to relocate refugees. That would also mean taking on the other Central European problem child, Poland, which has taken the same hard line. Countries on the frontline of migration such as Italy have pushed for infringement proceedings to be launched and it could help the Commission in its court case against Hungary and Slovakia, which objected to being told they must take in refugees. But it could make harder to reach a deal on reform of EU asylum law.

3. Open a rule-of-law procedure

This was the route taken in the case of Poland and, in the worst case scenario, could lead to the suspension of a country's voting rights. But the Commission seems reluctant to go down this path, mainly because Budapest is prepared to talk to Brussels whereas Warsaw is not. As in Poland's case, securing unanimity among the EU members countries for suspending voting rights would be extremely difficult.

4. Cut off the money

In the 2014-2020 budgetary period, Hungary is slated to receive around €29,6 billion in EU funds to finance motorways, railways, energy projects and other schemes in a country whose GDP is around €126 billion a year. It's an important source of cash for Budapest but the likes of Italy and Sweden are keen to claw back some EU funding if Central European countries are reluctant to host refugees. However, changing the EU's budget rules before 2020 would be impossible.

5. Send in the independent experts

The European Parliament has already approved a new mechanism for monitoring the rule of law which would set up a panel of independent experts to make country-specific recommendations during an annual fitness check of each EU member. The scheme's backers say it would make life easier for the Commission because it would be less political. But there's a problem. “Timmermans knows that he can’t propose [a new monitoring process] because he knows he’ll lose. He has to make sure there’s enough support in Council before he can put a proposal on the table,” said Israel Butler, director of advocacy at the Civil Liberties Union for Europe.

Harry Cooper contributed to this article.

This article has been updated to correct the procedure to be followed to kick a party out of the EPP.