Austria is planning to impose border controls and possibly deploy troops to cut the number of migrants crossing from Italy, defence officials said.
The move has drawn a warning from the Italian government and reigniting a row over Europe's handling of the refugee crisis.
Tensions between European Union countries over how to share the burden of migrants flared in 2015 when hundreds of thousands, many fleeing wars in Africa and the Middle East, began arriving in EU territory, mainly via Greece, and headed for Germany, Austria and other nearby affluent states.
Austria took in more than 1% of its population in asylum seekers at the time, which helped increase support for the far-right Freedom Party.
Keen to avoid another influx, it said it would introduce controls at the busy Brenner Pass border crossing with Italy if one materialised there.
That has not yet happened but Italy recently asked other EU countries to help it cope with a surge in migrants reaching its southern Mediterranean shores from Africa, raising concern in Austria that many will soon show up at its border with Italy.
That is a political hot potato in Austria, where a parliamentary election is scheduled in October with immigration shaping up as a central issue.
Austrian Defence Minister Hans Peter Doskozil told the mass-circulation Kronen Zeitung newspaper that he expected restrictions would be introduced along the Alpine boundary with Italy "very soon".
Other Austrian officials, including Interior Minister Wolfgang Sobotka, who oversees crossings like Brenner, said there was currently no reason to introduce controls and Austria remained vigilant, a stance Vienna has repeated for the past year.
Echoing his counterpart, Italian Interior Minister Marco Minniti said there was "no emergency" at the Brenner Pass, and Italian and Austrian police were cooperating perfectly.
"I am frankly surprised by the comments" from Mr Doskozil, Mr Minniti said in a statement.
"This is an unjustified and unprecedented initiative which, if not immediately corrected, will inevitably create repercussions on security cooperation."
An Austrian defence ministry spokesman said controls would include Brenner and that four armoured vehicles had already been deployed to the area to block roads, with 750 troops poised to be brought in within 72 hours to deal with emergencies.
"These are not battle tanks. These are armoured vehicles without weapons which could block roads. These were already used during the refugee crisis of 2015/16 at the Spielfeld border crossing (with Slovenia)," he said.
Austria coordinated with nearby Balkan countries last year to effectively close what was then the main route into Europe for migrants.
The move drew complaints at the time that it was undermining the EU's principle of free movement, though Austria says it did what it had to do to safeguard its borders.
Italy, alongside other states on the bloc's fringes, has complained it is now bearing the brunt and the cost of the migrant crisis.
It said last year that any plans to introduce controls at the Brenner Pass, a major road and rail link between northern and southern Europe, would break EU law.