BERLIN (AFP) - Germany has placed 4,000 troops on standby for this weekend alone to help with incoming refugees, Defence Minister Ursula von der Leyen said on Friday.

The troops will be able "to help out in emergency cases" and more could be called up if necessary, she said, in remarks reported by the news magazine Der Spiegel.

"We still have room to scale this up," she said, after Germany last weekend also mobilised thousands of troops to help with a record influx of 20,000 refugees, most of whom came on trains from Hungary via Austria.

The troop's watchword would be to exercise "maximum goodwill" toward the asylum-seekers, she said, according to pre-released excerpts from the article in Saturday's edition.

So far this year, 450,000 refugees have arrived in Germany, including 37,000 in the first eight days of September alone, Vice Chancellor Sigmar Gabriel told parliament on Thursday.

With thousands arriving every day, refugees are being housed in old schools, office blocks and even army barracks, with the army saying Thursday it was now putting up 14,500 refugees in 41 locations.

Von der Leyen said more refugees would be housed in military facilities, separated by security fences from soldiers' barracks, which was already the practice in dozens of locations nationwide run by the Bundeswehr, Germany's armed forces.

German Foreign Minister Frank-Walter Steinmeier said Friday in Prague that Germany expects 40,000 new migrants at the weekend. The figures were not confirmed by the German federal police or interior ministry.