The International Olympic Committee has launched a full investigation after discovering that hundreds of migrants who worked on the Sochi Games have not been paid.

IOC spokesman Mark Adams said the Committee had met with human rights activists in Sochi who had submitted a “full list” of 200 workers who had not been paid by Russian firms.

“Following that we instigated a full investigation,” he told reporters.

“I think they (Russia) investigated some 500 companies, all the companies that they could identify of having been involved in the construction,” he added.

Thousands of migrant workers, largely from the poorest ex-Soviet Central Asian states of Tajikistan, Kyrgyzstan and Uzbekistan were involved in the frenetic push to build the Sochi infrastructure on time.

Adams said that while the process of ensuring all workers were paid what they were due was not finished, the Russian authorities were making progress.

“But we can certainly say that a lot of the cases of people not being paid have been followed up. A lot of companies have been investigated, a lot of companies have been fined.”

He said the Russian side was making a “good job” of ensuring the money was being paid, a complex process given that it involved checking transfers made outside the country.

Transfers from migrants working in Russia back home make a crucial contribution to the economies of Central Asian states and is estimated to make up one half of the GDP of Tajikistan.

According to Human Rights Watch, migrant workers have been subjected to a litany of abuses in Sochi with employers “failing to pay their wages, confiscating workers’ passports, and forcing them to toil up to 12 hours a day.”