European countries should adopt Donald Trump-style travel bans to counter a wave of Islamisation supposedly sweeping the continent, the Dutch anti-immigrant politician Geert Wilders has said.

Wilders, the leader of the Netherlands’ Freedom party (PVV), made his comments at a gathering of far-right leaders in Prague. He also urged Europe to adopt Australia’s tactics in turning back migrant boats and to build new border walls, as Trump has vowed to do along the US frontier with Mexico.

Wilders was flanked during his press conference by France’s Front National leader, Marine Le Pen, and Tomio Okamura, the leader of the Czech Freedom and Direct Democracy party (SPD), which finished joint third in recent parliamentary election with nearly 11% of the vote.

Security was tight at the press event, held at a hotel just off Wenceslas Square, apparently in recognition of death threats against Wilders in response to his fierce denunciations of Islam.

Wilders, who was convicted last year by a Dutch court for incitement against Moroccans, cited US research he claimed showed that the Czech Republic would be bordered to the north, south and west by countries that were more than 20% Muslim by the middle of the century if current demographic trends continued.

“It will be almost as if you are bordering a kind of Gaza Strip on almost every border,” he said.

“We must adopt a totally new strategy. We must have the courage to restrict legal immigration instead of expanding it, even if we sometimes have to build a wall.”

Trump’s travel ban, which applies to six Muslim-majority nations plus North Korea and Venezuela, has been one of his most controversial policies. It has been the subject of various challenges in court, and rulings that have overturned and suspended it. The US supreme court ruled this month that it could be implemented for now while numerous challenges were resolved.

The Prague gathering came at an encouraging moment for the organisers, the European parliament’s populist Europe of Nations and Freedom grouping,. The Austrian Freedom party (FPO), one of the participants, became the only far-right party in government in a western European state on Friday, after joining a coalition with the conservative People’s party.

That followed a year of setbacks for Wilders and Le Pen, who failed to make the electoral breakthroughs many had forecast. The PVV remains in opposition in the Netherlands after a poorer than predicted parliamentary election result last March, and Emmanuel Macron beat Le Pen in the second round of France’s presidential poll in May.

A similar meeting last January in the German town of Koblenz was held amid euphoric expectations of major successes in 2017.

Le Pen said Europe’s rightwing groups were linked by a belief that the European Union was a “catastrophic, disastrous organisation” and that the migration flows were “unbearable”. She also praised Okamura, with whom she said she had been working for many months.

Tokyo born-Okamura, the son of a part-Japanese father and Czech mother, said the parties were defending European values.

Wilders, Le Pen and Okamura later received rousing ovations at the weekend’s main event, a conference at the Top Hotel, a nondescript Communist-era building in Chodov, a bleak suburb several miles from the centre of Prague.

The venue was cordoned off, a police helicopter hovered overhead and riot police monitored two groups of leftwing protesters.

“The dangerous thing is that the extreme views we see on display here have entered the mainstream, with even the Czech Social Democrats accepting them,” said Honza, a protest organiser who declined to give his full name for safety reasons.

Similar mistrust was evident inside, where security personnel scrutinised journalists closely and escorted them to and from a sectioned-off area.

The independent British MEP, Janice Atkinson, a former Ukip member, invoked the Czech fight against communism, the failed 1968 Prague Spring and Margaret Thatcher to encourage her audience to campaign for a Czexit referendum that could enable the Czech Republic to follow Britain out of the EU.

“As Margaret Thatcher said, Europe is stronger precisely because France is France, Spain is Spain, Britain is Britain and, just as important, Czech is Czech,” she said. “Long live the Europe of nations. Long live the Czech Republic.”