Austria has finished preparations for a fence that would cover 30 kilometres of its 300-kilometre border with Hungary, a police spokesman has told dpa.
The fence could be erected quickly in case the number of migrants arriving from the East increases from the current low levels of 20 to 30 a day.
"It's ready," the spokesman said.
Austria has been implementing strict migration policies to keep the number of asylum claims below 37,000 this year, compared to last year's 90,000.
Vienna is trying to goad and pressure Budapest to take back asylum seekers that have entered Austria via Hungary, under the European Union's Dublin rules.
The government chiefs of both countries, Austria's Christian Kern and Hungary's Viktor Orban, are set to meet in Budapest on July 26 to discuss migration issues.