Science broadcaster Dr Karl Kruszelnicki is backing away from his role as the Abbott government's spokesperson for the Intergenerational Report, describing the document as "flawed" and "fiddled with" by the government.

Dr Kruszelnicki, known to many as "Dr Karl", has been splashed on billboards, bus shelters and TV screens across Australia as the official face of the much maligned report in an advertising campaign estimated to cost millions.

Dr Karl said previously he had not read the report before signing up as its spokesman and is now critical of its approach to climate change and funding cuts to the CSIRO.

"As far as I can see, it's a flawed report," Dr Kruszelnicki told Fairfax , signalling out the lack of significance given to climate change.

"In no way am I endorsing the government's stance on climate change. I think it is incredibly short-sighted," he said.

The report is intended to provide a snapshot of Australia's economic and social outlook for the next 40 years but it was criticised by Labor for being "highly political document" when it was released in early March.

The focus on climate change had been reduced from an entire chapter in the 2010 report to just three-and-half pages this year.

The report and the advertisements in which Dr Kruszelnicki appears trumpet the need for increased spending on scientific research and development.

But Dr Kruszelnicki has criticised the Abbott government's decreased funding for scientific research in the past, with cuts of $140 million to the CSIRO drawing particular scorn in his tweets.

"The only reason I agreed to do it (promote the report) is because I was told that it would be independent, bipartisan and non-political," he told Fairfax, although he admitted in the past he did it for the money because he gets "bugger all" from the ABC and Sydney University.

"If it turns out to have been fiddled with or subject to political interference from one side of politics I would deeply regret playing any part in it whatsoever."

He told the ABC this morning there had been a backlash against him for taking the gig. "Hate emails, hate Twitters that I am to blame for the one-quarter of scientists being fired from CSIRO, that I am to be blamed for somebody's daughter having to pay a huge amount for her education for a science degree," he said.

Dr Kruszelnicki said his independent stance on the reports is now uncertain.

In Senate hearings last month Treasury deputy secretary Nigel Ray described the report as a "document of the Treasurer" Joe Hockey.

A spokesman for Mr Hockey said the report was a product of the treasury department, "as has been the case with the previous three documents".