Slovenia's army has begun rolling out razor wire along the border with Croatia, a report says, in a move billed by the government to better manage the influx of asylum seekers.

Slovenia last month suddenly found itself on the Balkans route taken by thousands of asylum seekers heading to northern Europe, after Hungary sealed its borders with Croatia and Serbia.

More than 170,000 asylum seekers have passed through the small EU member state of 2 million people since mid-October, all but a handful heading for Austria and beyond.

Prime minister Miro Cerar announced on Tuesday the government planned to build "obstacles" along parts of its frontier with Croatia, an outer border of Europe's passport-free Schengen zone.

"These obstacles, including fences if needed, will have the objective of directing migrants towards the border crossings," Mr Cerar told a news conference. "We are not closing our borders."

An AFP reporter in Gibina in north-eastern Slovenia said on Wednesday morning soldiers were erecting rolls of the razor wire to about waist-height across fields.

Media reports said that troops were also installing a razor-wire barrier on the banks of a river near Obrezje in southern Slovenia, just across the border from Zagreb, and that there were plans to erect another one at a third location.

Mr Cerar said the measures were aimed at avoiding a "humanitarian disaster" caused by an expected sharp rise in asylum seeker numbers this week following a recent dip.

Slovenia's prime minister Miro Cerar said the government planned to build "obstacles" along parts of its frontier with Croatia. ( AFP )

He also said Austria — the next country along on the asylum seeker trail — was planning to restrict the daily number of new arrivals to 6,000, creating a backlog in Slovenia.

Austria expects a record 95,000 asylum claims this year, an official said on Wednesday, but the government has so far not announced that it will limit the number of asylum seeker entries.

But its squabbling coalition government is discussing similar measures along the border with Slovenia, with a decision now expected on Friday.

Croatian interior minister Ranko Ostojic on Wednesday labelled Slovenia's barrier an "unnecessary waste of money".

"No wire can prevent migrants from finding their path [to their desired destinations] ... it would have been more better to build reception centres, temporary shelters as Croatia did," local media quoted Mr Ostojic as saying.

Slovenia's actions came as European leaders were due to meet African counterparts in Malta to discuss the asylum seeker crisis, which has driven a wedge between member states and boosted populist parties.

Meanwhile, at least 14 people, including seven children, drowned after a boat carrying asylum seekers sank off Turkey's Aegean coast while trying to reach Greece on Wednesday.

AFP