Nationalist Orban, who faces a close parliamentary election next year for the first time in more than a decade, was re-elected chairman of Fidesz on Sunday.

"After communist bureaucracy ... we don't want new dictates this time from Brussels," Orban told cheering party delegates, adding Hungary would reject western liberalism.

"We will not give up the right to defend our borders, to stop migrants ... we insist that marriage in Hungary is between a man and a woman, a father is a man and a mother is a woman ... and they should leave our children alone."

In power since 2010, 58-year-old Orban has cast himself as a defender of Hungary's cultural identity against Muslim migration into Europe and a protector of Christian values against Western liberalism.

That has won him domestic popularity, especially among core Fidesz voters, but brought criticism from rights groups and LGBT campaigners.

Orban said the EU must be reformed and Hungary's aim was to achieve change, not leave the bloc that it joined in 2004.

"We don't want to leave the EU at all, they can't get rid of us so easily," he said. "We want to keep our sovereignty and we don't want to find ourselves in a united states of Europe, instead of integration."

In the election, likely in April 2022, Orban will face a united front of opposition parties including the Socialists, liberals and the formerly far-right, now centre-right, Jobbik.

The six-party alliance is led by Peter Marki-Zay, a 49-year-old Catholic conservative, father-of-seven and small-town mayor who seems to embody the traditional values Orban publicly champions and is seen as a tough challenger. nL8N2RI2T5

In the past weeks Orban has made a number of spending pledges, including a $2 billion income-tax rebate for families, and stepped up his anti-immigration rhetoric.