Austria has moved four armoured vehicles close to its border with Italy to guard against migrants and will likely set up controls on a key trade crossing "very soon", defence ministry officials said on Tuesday.

The planned controls will include the busy Alpine Brenner pass, a defence ministry spokesman said - a move that Italy warned last year would break EU rules on free movement.

"I expect border controls will be introduced very soon," Defence Minister Peter Doskozil told daily newspaper Kronenzeitung in an interview published on Tuesday.

Both Italy and Austria are members of the European Union's Schengen open-border zone, but free movement has been jeopardised by the reimposition of controls at many crossings across the bloc since the surge in migrants seen in 2015/16.

There was no immediate comment from Italy or EU officials.

Doskozil's spokesman said there was no concrete timetable for the new controls. "But we see how the situation in Italy is becoming more acute and we have to be prepared to avoid a situation comparable to summer 2015."

Italy has taken in more than 80,000 refugees and migrants so far this year, most of whom arrived by boat from Africa, making Italy the main point of entry to Europe.

Austria has already moved heavy equipment to the province of Tyrol, which borders Italy, including four armoured vehicles to block roads, the spokesman said.

"These are not battle tanks. These are armoured vehicles without weapons which could block roads. These were already used during the refugee crisis 201/16 at the Spielfeld border crossing (with Slovenia)."

The army would also be able to send in 750 soldiers within 72 hours to deal with emergencies, the spokesman added.

Controls at the Brenner pass would be particularly sensitive as the border there cuts across two communities that feel closely connected - Austria's Tyrol and Italy's South Tyrol. South Tyrol was once part of the wider Austro-Hungarian empire but was annexed by Italy in 1918.

The European Commission plans to present a set of measures to reduce the migrant flow across the central Mediterranean later on Tuesday.