Hungary took over the six-month rotating presidency of the bloc in July and almost immediately went to Moscow and Beijing in what was described as a "peace mission" despite none of his EU partners being aware, or mandating him to do so.

He also left a NATO summit early to meet former U.S. President Donald Trump. Orban's foreign minister has since questioned the EU's role in Ukraine.

"We will discuss what has happened and positions taken by the Hungarian government," Borrell said, describing them as "unacceptable".

Some member states would like the bloc to show a tougher stance on Budapest.

Among the ideas would be to boycott or downgrade the attendance of ministers at an informal meeting in Budapest at the end of August, although there is division among countries on its utility.

German Foreign Minister Annalena Baerbock told reporters on arrival in Brussels that Borrell represented EU foreign policy for the ministers and that it was "not surprising that the ego trips" had irritated many.

Luxembourg's Foreign Minister Xavier Bettel said he would go to the informal meeting at the end of August saying it was important to keep the dialogue with Budapest.

"Ignoring or not choosing dialogue would be an error," he said.

Orban, a critic of Western military aid to Ukraine and who has the warmest relations of any EU leader with Putin, has also repeatedly held up decisions for military aid to Ukraine.

Speaking in a social media post ahead of the meeting on Monday, Hungary's Foreign Minister Peter Szijjarto criticised the bloc.

"For weeks now, the Brussels foreign bureaucracy and the leaders of some EU countries have been grinding their teeth over our peace mission, out of frustration/envy/exposure of their failed strategy," he said, adding the trips had opened the door to further diplomacy.

"All we get from our Brussels and European friends is a childish sit-in boycott and verbal karate," he said.