US Vice-President JD Vance has insisted he was right to stage a two-day campaign visit to back Hungarian Prime Minister Viktor Orbán five days before he was voted out of office by opposition party Tisza's landslide victory.

Insisting Orbán was a "great guy" who did a "very good job", Vance told Fox News he was "one of the few European leaders we've seen who's been willing to stand up to the bureaucracy in Brussels".

While he was sad Orbán had lost, he was sure the US would "work very well" with the new government, he said.