By Karolos Grohmann
BERLIN, Oct 25 (Reuters) - German soccer chiefs on Friday launched an attack on the 2022 Qatar World Cup, calling it a "burden on football" because of the likely shift in dates from a traditional summer tournament to a winter competition.
German football association (DFB) president Wolfgang Niersbach, re-elected until 2016 earlier on Friday, also said he would join forces with unions to ask FIFA about migrants' working conditions in the country following allegations of worker deaths on construction sites.
"It is a burden for all of football," Niersbach said in a federation meeting in Nuremberg. "It is a challenge on an international level that I have not experienced in my professional career.
"If a new date is found for the winter, which in my view is the only alternative, then the effects will be felt across the world."
World soccer's governing body FIFA has been under mounting international criticism since awarding the World Cup to the tiny yet cash-rich Gulf state in 2010 where summer temperatures can rise as high as 50 degrees Celsius.
Qatar was awarded the 2022 World Cup at the expense of rival bids from the United States, Australia, Japan and South Korea.
FIFA President Sepp Blatter has since said it was a mistake to award a summer tournament to Qatar and is now looking for dates in the winter.
"FIFA must provide answers to burning questions by the end of 2014 early 2015," Niersbach said.
A change of date from a traditional summer event would mean a major shift of the calendar for every league for one or even two seasons to accommodate it.
"It is more than just irritating when European club football is made to act as a repair shop for what looks like a wrong decision," said German football league (DFL) President Reinhard Rauball at the same meeting.
Rauball, who heads the top professional leagues in the country, also said working conditions on World Cup sites were crucial.
"It is clear that no World Cup should be built on a system that resembles slavery," Rauball said.
Britain's Guardian newspaper reported a few weeks ago dozens of Nepali workers had died on building sites in Qatar over the summer while the International Trade Union Confederation said 4,000 lives would be at risk before the tournament started.
Organisers of the Qatar tournament have said workers' rights are written into the contracts of those involved in the 2022 World Cup and they would try to ensure these were enforced. (Reporting by Karolos Grohmann; Editing by Alison Wildey)