"The daily number of migrants being turned back has risen from 60 in December to 200 since the start of the year," David Furtner, police spokesman in Upper Austria state, told AFP.
He said those being sent back were migrants -- mostly Afghans as well as Moroccans and Algerians -- who did not want to apply for asylum in Germany but in other countries, notably Scandinavia.
Austria is a major transit country for the hundreds of thousands of migrants and refugees seeking to enter the European Union, mostly via Upper Austria state at a rate currently of 1,000-2,000 per day.
Last week, Sweden, a favoured destination for many of the migrants, sought to stem the flow by imposing controls on travellers from Denmark.
Denmark in turn introduced spot checks on arrivals from Germany.
Austria meanwhile has moved to tighten controls on its border with Slovenia, with Carinthia, one of two Austrian states bordering Slovenia, turning back 1,652 since January 1, according to police.
Austrian Chancellor Werner Faymann said Monday that Vienna was looking into the legality of turning away "economic migrants" -- as opposed to bona fide refugees -- at its borders.
"What is certain is that soon we are going to become more active at our borders," Faymann said in an interview with the Kronen-Zeitung daily to be published on Tuesday.
Police spokesman Furtner said that almost all those turned back by Germany simply try again to enter the country, with most succeeding via other routes, Furtner said.