Hungarian prime minister Viktor Orban has again spoken out against the influx of migrants into Europe, saying it will not solve the continent's problems.

The outspoken leader said that efforts should be made instead to encourage European families to have more children who can help the region prepare for the future.

Orban, who has characterized this year's migrant crisis as a deliberate left-wing conspiracy designed to erode European identities, said that bringing in new immigrants won't help with Europe's ageing populations and economic stagnation.

Idea: Viktor Orban, pictured speaking at a conference in Budapest on Thursday, said that migrants cannot solve the problems of ageing populations and ailing economies in Europe

Speaking at a conference on Thursday in Budapest, the Hungarian capital, Orban said: 'Europe cannot build its future on immigration instead of families.'

He said instead that governments need to great incentives for its existing citizens to have more children, warning that 'the survival of our civilization and our culture is at stake.'

Orban, the leader of the ruling right-wing Fidesz party, has been using tax breaks, housing subsidies and other incentives to encourage families to have more children.

Hungary's population has declined every year since 1980, and in 2011 fell below 10 million for the first time since 1960.

His words come less than a week after a more strident intervention, in which he accused U.S. billionaire George Soros of betraying Europe by supporting migrants in a bid to change the character of Europe.

Orban said a conspiracy of left wingers, influential money movers and unelected leaders were undermining EU attempts to deal with the crisis.

The Hungarian leader has been a champion of hardline anti-migration policies, and built razorwire-topped fences on Hungary's southern borders with Serbia and Croatia to keep out migrants.

Issue: Migrants are seen walking in Slovenia last week, redirected after Hungary closed its border by erecting a barbed wire fence

In a speech in Budapest today, Orban cited Hungarian-born Mr Soros as an example, saying the plans of 'well organised money movers, those thinking beyond nation-states and leader who have never been elected' could come to reality.

Conspiracy? Orban has accused Hungarian-born leftwing billionaire George Soros as being part of a left-wing conspiracy behind the migrant crisis

He said: 'Europe has been betrayed, if we don't stand up for it, the continent will no longer be for those citizens living here.'

Mr Orban also added how it was 'hard to imagine' that large European states with 'huge well-functioning intelligence services' were not prepared for the influx of several thousand refugees to Europe each day.

Hungary has said it plans to challenge the EU's mandatory quota plan for refugee relocation, and not take in any asylum-seekers or migrants sent back from western Europe.

'Who in Europe voted to allow people to arrive illegally in their millions and then be distributed?" Orban asked during a radio interview.

'What is happening today has no democratic basis," he said, adding that the EU was moving from organisation and legality to 'anarchy.'

'The people of Europe are beginning to wake up, they have realised that immigration is a cultural question, our identity is at stake,' he said.

More than 700,000 people fleeing war and poverty, many of them refugees from conflict in Syria, have arrived in Europe so far this year, with the bulk of them heading for Germany and Sweden.