The pro-Russian businessman has been living in Austria for two years since leaving Ukraine and being unable to return there due to threats to his life following the revolution in 2014.
He had been arrested in Vienna in 2014 after the US put out an extradition request, saying that Firtash is wanted in connection to bribes paid to Indian officials over a titanium-mining deal, which he denies.
He was released from detention after posting bail of €125 million, thought to be the highest ever in the history of Austria.
An Austrian judge then later ruled against the US extradition request in May 2015 saying that it was politically motivated. The request had come at a time of the Ukrainian revolution, when US authorities were trying to close in on Putin's inner circle to pressure him to pull out of the country.
Firtash, one of Ukraine's richest businessmen, made his fortune by exploiting the instability and chaos which followed the Soviet collapse and acting as the middleman trading Ukrainian food supplies for Central Asian gas.
He went on to make money through the chemical, banking and media industries, becoming a close associate of the former Ukrainian president Viktor Yanukovych. Along with many other allies, Firtash has not been able to safely live in Ukraine since the new pro-EU government was formed in 2014.
Now the 50-year-old billionaire has told Bloomberg news that he wants to return to his country, where he is strongly critical of the government that he says has “brought the country to the edge of catastrophe”.
“If they remain in power longer, this may only make things worse,” he said. “I am not happy with the fact that our country is being governed from abroad, that Americans are governing Ukraine. They may be very smart, I don't have anything against the US but there is a problem. Ukraine is still an independent country and these are Ukrainians who should govern Ukraine and not be under external management.”
According to media reports, he had planned to return to Ukraine towards the end of last year but decided against it after the government said he would be arrested at the airport.
He is currently free to travel, but the US is appealing the extradition ruling.