The companies are plunging money into accelerator programmes, designed to provide startups with funds and expertise, in the East London hub.
Vodafone said yesterday it plans to have its operation up and running by the end of the year, and hopes to replicate the success which it has seen on its similar project in Silicon Valley.
Barclays is providing backing to Central Working, a programme that provides office space to small businesses. Several other firms including those based in Italy and Japan are also investing in projects. The deals are due to be announced at a summit later today.
Tech City has been a pet project of the government, with David Cameron and George Osborne keen to rival the startup scene in California. Google and Amazon have recently unveiled new developments in the area.
Osborne said: “The government is determined to make Britain the technology centre of Europe, with London’s Tech City at its heart.”