Last night, Hunt received a protest letter from Slaughter and May, the law firm representing the Guardian Media Group, Trinity Mirror, the Telegraph Media Group, BT and the Daily Mail and General Trust.
News Corp is understood to have suggested separating Sky News from Sky in order to persuade Hunt not to hand the firm's bid to take full control of Sky to the Competition Commission for a lengthy review.
According to the Financial Times, the letter claims that it would be unacceptable to hive off Sky News as a solution to concerns about the Sky takeover.
The media firms have consistently argued that a combined News Corp-Sky would pose a significant threat to media plurality in the UK.
The letter points out that in order for the Sky News proposal to be effective, the broadcaster would have to be completely separated from Sky, including full independence on editorial, operational and financial grounds.
However, it notes that the loss-making Sky News would most likely face significant challenges surviving under those circumstances.
The lawyers concluded by claiming that the issues surrounding the Sky takeover are sufficiently complex so as to require a full Competition Commission investigation.