The first surgeon-general appointed by US President George Bush has accused his Administration of political interference and muzzling him on issues such as embryonic stem cell research.

Dr Richard Carmona, a Bush nominee who served from 2002 to 2006, is one of a growing list of present and former Administration officials to charge that politics often trumped science within what had previously been largely nonpartisan government health and scientific agencies.

Dr Carmona told the House Committee on Oversight and Government Reform that political appointees routinely scrubbed his speeches for politically sensitive content and blocked him from speaking out on public health matters.

The Administration, he said, would not allow him to speak or issue reports about stem cells; emergency contraception; sex education; or prison, mental and global health issues. Top officials delayed for years and tried to water down a landmark report on second-hand smoke, he said.

Released last year, the report concluded that even brief exposure to cigarette smoke can cause immediate harm.

Dr Carmona said he was ordered to mention President Bush three times on every page of his speeches. He also said he was asked to make speeches to support Republican candidates.

"Anything that doesn't fit into the political appointees' ideological, theological or political agenda is often ignored, marginalised or simply buried," he said. "The problem with this approach is that in public health, as in a democracy, there is nothing worse than ignoring science, or marginalising the voice of science for reasons driven by changing political winds."

A former professor of surgery and public health at the University of Arizona, Dr Carmona said he was told not to speak out during the national debate over federal funding for embryonic stem cell research, which President Bush opposes.

"Much of the discussion was being driven by theology, ideology, (and) preconceived beliefs that were scientifically incorrect," he said. "I thought, this is a perfect example of the surgeon-general being able to step forward, educate the American public … I was told the decision had already been made — 'stand down, don't talk about it.' That information was removed from my speeches."

White House spokesman Tony Fratto rejected claims of political interference, saying Dr Carmona had all the support he needed to carry out his mission. "As surgeon-general, Dr Carmona was given the authority and had the obligation to be the leading voice for the health of all Americans," Mr Fratto said. "It's disappointing to us if he failed to use his position to the fullest extent in advocating for policies he thought were in the best interests of the nation."

Dr Carmona said that when the Administration touted funding for abstinence-only education, he was prevented from discussing research on the effectiveness of teaching about condoms as well as abstinence. Officials even discouraged him from attending the Special Olympics because, he said, of that charitable organisation's longtime ties to a "prominent family" that he refused to name.

"I was specifically told by a senior person, 'Why would you want to help those people?' " Dr Carmona said.

When asked after the hearing if that "prominent family" was the Kennedys, Dr Carmona responded: "You said it. I didn't."