Sources close to the PMO refused to comment on the allegations calling the matter "subjudice."
The charges that Law Minister Ashwani Kumar met CBI director Ranjit Sinha and asked for changes to the CBI's status report before it was given to the Supreme Court were detailed in national daily Indian Express.
When asked if the Law Minister had pressured him at a meeting to tone down the report, the CBI director did not deny the charges, and said he cannot comment on the report. (Reactions: who said what)
The Supreme Court had asked Mr Sinha last month to state in writing that the CBI's status report had not been reviewed by "the political executive."
The opposition has said that the controversy exposes what it has always alleged-that the CBI is influenced by the government and that it's putative independence is a farce. (Government trying to use CBI to save PM, says Sushma Swaraj)
"This is evidence of the government's pressure on the CBI to save the Prime Minister," BJP's Sushma Swaraj tweeted.
The CBI told the Supreme Court last month that private firms had misrepresented information to win coal licenses and that the government had not verified their credentials.
The government was first hit by allegations of "Coal-Gate" scandal when its auditor said in March 2012 that the country lost 1.86 lakh crores because coal fields were allocated without a transparent bidding process. But the government argues that its policy was not focused on revenue, but on ensuring industrial and infrastructural development.