By Shadia Nasralla

VIENNA (Reuters) - Austria's treatment of asylum seekers at a center near Vienna is "scandalous", Amnesty International said on Friday, accusing the country of neglecting homeless and hungry migrants who are flocking in record numbers to western Europe.

As many as 2,000 refugees at an asylum processing center in Traiskirchen, south of the capital, have for weeks had to endure heat of around 40 degrees Celsius (104 Fahrenheit) and rain storms with only blankets to shelter them as they waited in the open air.

Children who had fled alone from countries like Afghanistan and Syria have been offered no psychological care, women have had to use mixed showers, and a baby with a concussion was left next to a bus on a parking lot, the human rights group said.

"What we found is totally scandalous ... because human rights are being violated there massively for no reason related to resources," Heinz Patzelt, the head of Amnesty Austria, told Reuters after publishing a report on Traiskirchen.

Countries on the European Union's western and southern edges are struggling to cope with the numbers of migrants arriving by land and sea, many from war zones. The United Nations refugee agency called conditions on the Greek island of Kos "totally shameful" for an EU country.

"It's not that Austria cannot do it. Austria is incapable of organizing itself in a way that's dignified for humans," Patzelt said.

Austria's Interior Ministry said in response that the rise in the numbers of refugees had created an exceptional situation and that it was working to improve things.

Thousands of people have fled through the Balkans to Austria - a country of 8.5 million people - pushing the number of asylum requests to 28,300 in the first six months of this year, more than the total for all of 2014.

"It's only possible to get a sustainable solution on the level of the entire country and of Europe," Interior Minister Johanna Mikl-Leitner said.

Vienna, which has called for binding quotas to distribute migrants across the Europe Union, is sending around 500 asylum seekers to Slovakia to relieve pressure on Traiskirchen and is working on a new law for handling refugees.

The European Union last month failed to agree on how to spread 40,000 asylum seekers among its members.

(Editing by Robin Pomeroy)