PN leader Adrian Delia has written to the President of the European People's Party, Donald Tusk, calling for an urgent videoconference summit to decide on the way forward regarding Hungary’s ruling Fidesz party membership.

Thirteen European centre-right parties on Thursday called for their political group to expel Hungary's ruling Fidesz party after its leader Prime Minister Viktor Orban assumed emergency powers amid the COVID-19 crisis.

Orban insists he must rule by decree to tackle the spread of the coronavirus epidemic. But many, including some of his allies in the EPP, say his power grab has gone too far.

In his letter to Tusk, Delia said the current situation with the healthcare and economic fallout of the COVID-19 crisis represented a challenge for the European Union, but also an opportunity to re-affirm values.

“I believe this crisis has shown that those values are now under threat under the guise of open-ended emergency legislation passed in Hungary. The situation regarding Fidesz’s membership of the EPP family has now reached a point where the EPP must speak with one voice across our parties."

The Scandinavian, Greek, Belgian, Lithuanian, Czech and Slovak conservatives who signed Thursday's statement calling for Fidesz to be kicked out of the EPP do not represent a majority of the group.

But their letter strengthens the hand of its addressee, party chairman Tusk, the former Polish leader and president of the European Council, who is pushing the EPP to distance itself from Orban.

The signatories call on the EU executive, the European Commission, to "address the situation in Hungary forcefully" and brand Orban's move a "violation of the founding principles of liberal democracy and European values".

Shortly before the parties' letter was made public, European Commission chief Ursula von der Leyen said she was "particularly concerned" about Hungary and promised to monitor the situation.

And 13 EU members, including heavyweights France and Germany, without explicitly naming Hungary, warned Wednesday against "violations of the principles of rule of law, democracy and fundamental rights".

The EPP is the biggest single voting bloc in the European Parliament and the party of both von der Leyen and Germany's Chancellor Angela Merkel.

But it is not in itself a majority, and some EPP parties have wanted to keep Orban's Hungarian MEPs on board in the centre-right grouping to avoid them siding with eurosceptic populists.

The letter was signed, however, by the leaders of 13 conservative or centre-right parties, including two serving prime ministers; Kyriakos Mitsotakis of Greece and Erna Solberg of Norway.