"It's the 12th hour [and] we're totally unprepared," he said.

"A few weeks ago, we said we'd do it reasonably, but in the meantime things went mad - it's unclear at the government who the responsible people are ... people who should be dealing with the EU presidency resign or they're dismissed," he added.

He said it was a "political necessity" to replace the government, which he called a "crash of Romanian democracy".

"There is no prospect of good governance and involvement in European affairs. This is very serious," Iohannis said.

Romania is due to take over the rotating EU chairmanship from Austria on 1 January, for six months.

The tasks include preparing the agendas of member states' meetings at the EU Council in Brussels, chairing talks, and organising EU-themed symposiums at home.

They also include speaking on behalf of EU states at the European Parliament and in talks with European Commission officials.

Romania joined the EU in 2007 and its upcoming presidency, its first ever, was meant to show off its credentials on the EU stage at a time when it is angling to be let in to the EU's passport-free Schengen travel zone, as well as to shake off long-standing concerns on corruption and abuse of rule of law.

Iohannis spoke out three days after the minister in charge of preparing for its EU chairmanship, Victor Negrescu, resigned.

The minister left his post because the government was unhappy with his work in building relations with the EU commission, Rovana Plumb, the minister in charge of EU funds and acting education minister, said at the time.

Iohannis' mention of the "crash" in good governance referred to the fact the country was nominally led by prime minister Viorica Dancila, a former MEP, from the centre-left Social Democratic Party.

But the real leader is widely said to be the party chairman, Liviu Dragnea, who is barred from holding office due to a prior conviction for electoral fraud.

For his part, Dragnea lashed out at Iohannis moments after the president spoke at the mayors' meeting.

"Do not be fooled by the lies of Iohannis," he said at an impromptu press briefing.

"The government is ready to manage the presidency of the EU Council. Iohannis has done the country a major disservice," he said.

The president had "no proof" to back up his words, Dragnea added.

He also attacked Iohannis personally, saying that prosecutors had 17 ongoing "criminal files" opened against him linked to his official declaration of interests and statements of personal wealth.