The Gulf emirate's labour ministry named DLA Piper "to independently review all the claims made, and to report on their veracity to the ministry," Ali al-Kholeifi, the ministry's international affairs adviser, said late on Wednesday.
The ministry will "take all necessary measures to respond to these allegations once the report is ready," the QNA state news agency quoted him as saying.
"The government of Qatar takes its international commitments seriously, especially following recent allegations of violations" of the international convention on forced labour, Kholeifi said.
Qatar has denied claims in a report in Britain's Guardian daily that Nepalese construction workers at World Cup projects are being treated like "slaves".
"There is no slavery or forced labour in Qatar," said Ali al-Marri, chairman of the country's National Human Rights Committee.
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Last week's Guardian report said dozens of Nepalese have died working in Qatar in recent weeks, raising concerns about the country's preparations to host the World Cup.
Quoting documents obtained by Kathmandu's embassy in Doha, the newspaper said thousands of Nepalese -- at 370,000 the second largest group of labourers in Qatar after Indians -- faced exploitation and abuses amounting to "modern-day slavery".
Qatar has come under pressure to ensure the safety of migrant workers employed on the massive infrastructure projects needed for the tournament.
British Prime Minister David Cameron urged Doha to follow London's example, saying it built the 2012 Olympic venue without a single fatal accident.
In 2010 Qatar won the right to host the 2022 FIFA World Cup.
The FIFA executive committee is meeting on Thursday and Friday in Zurich to discuss the tournament's timetable after calls for it to be staged in winter because of the desert emirate's scorching summer.