A leaked cache of confidential files from the ride-sharing company Uber has revealed what journalists say are potentially illegal tactics used by the company to fuel its frenetic global expansion starting nearly a decade ago.

A joint media investigation involving dozens of news organisations found that company officials leveraged the at-times violent backlash from the taxi industry against drivers to garner support and evaded regulatory authorities as Uber looked to conquer new markets.

Gleaned from 124,000 documents dating from 2013-2017, the revelations are the latest hit for a company dogged by controversy as it exploded into a disruptive force in local transportation.

The cache includes text and email exchanges between executives, including Uber's co-founder and former chief executive Travis Kalanick, who was forced to resign in 2017 following accusations of brutal management practices and multiple episodes of sexual and psychological harassment.

"Violence guarantee(s) success," Kalanick messaged other company leaders as he pushed for a counter protest amid sometimes heated demonstrations in Paris in 2016 against Uber's arrival in the market.

Uber's rapid expansion leaned on subsidised drivers and discounted fares that undercut the taxi industry, "often without seeking licenses to operate as a taxi and livery service," reported The Washington Post, one of the media outlets involved in the probe.

Drivers across Europe faced violent retaliation as taxi drivers felt their livelihoods threatened. The Post said the investigation found that "in some instances, when drivers were attacked, Uber executives pivoted quickly to capitalise" in order to seek public and regulatory support.

According to Britain's Guardian newspaper, Uber encouraged drivers across Europe to complain to the police when they were victims of violence, in order to use media coverage to obtain concessions from the authorities.

A spokesperson for Kalanick strongly denied the findings as a "false agenda," saying he "never suggested that Uber should take advantage of violence at the expense of driver safety."

Uber, however, placed the blame on previously publicised "mistakes" made by its leadership under Kalanick.

"We've moved from an era of confrontation to one of collaboration, demonstrating a willingness to come to the table and find common ground with former opponents, including labor unions and taxi companies," it said, noting that Kalanick's replacement, Dara Khosrowshahi, "was tasked with transforming every aspect of how Uber operates."

The reports say the files reveal Uber also lobbied governments to aid its expansion, finding in particular an ally in France's Emmanuel Macron, who was economy minister from 2014 to 2016 and is now the country's president.

The company believed Macron would encourage regulators "to be 'less conservative' in their interpretation of rules limiting the company's operations," the Post said. (AFP)