The culture secretary will be the focus of an inquiry by John Lyon, the parliamentary standards commissioner, over claims that he failed to register media donations.
Hunt has resisted urgent calls to resign after the Leveson Inquiry suggested that he had secretly supported News Corporation's bid to take full control of Sky.
Labour MP Stephen McCabe had written to Lyon about his concerns over "networking events" involving eight media industry groups. Culture minister Ed Vaizey had confirmed that he and Hunt attended the events while in opposition before the 2010 general election.
Vaizey's records stated that donations had totalled around £27,000, while McCabe claims that Hunt did not mention his entry in the register.
Hunt's spokeswoman said that he had amended the register since the complaint was raised by McCabe.
Lyon's office confirmed to The Guardian that an inquiry had been launched, but further details have yet to be confirmed.
Jeremy Hunt's former adviser Adam Smith will give evidence at the Leveson Inquiry next week.