Arnold Schwarzenegger, the California governor, was today under pressure to terminate his $5 million contract with bodybuilding magazines which advertise performance-enhancing supplements for schoolchildren.

Mr Schwarzenegger is being paid at least $1 million (£570,000) a year, over five years, to serve as a consultant for magazines including Flex and Muscle & Fitness, according to a report filed to the Securities and Exchange Commission

Mr Schwarzenegger, a former film star and Mr Universe, today rejected accusations that the deal represents a conflict of interest. Last year, he vetoed a Bill intended to regulate the use of performance-enhancing substances in high school sports.

It would have required student athletes to pledge not to use the supplements, and barred manufacturers from sponsoring school events.

Doug Heller, executive director of the Foundation for Taxpayer and Consumer Rights in Santa Monica, said: "He has broken his trust to the people by vetoing legislation to protect young people from dangerous supplements without ever telling us that he is earning millions of dollars from these companies."

The publications derive 70 per cent of their advertising revenue from adverts for muscle-building supplements.

In the August 2005 issue of Muscle & Fitness, 123 of the magazine's 256 pages feature ads for nutritional supplements such as Blast Cycle: Thermonuclear Pump Agent and Axis HT Pro-Testosterone Amplifier.

Senator Jackie Speier last night called on Mr Schwarzenegger to sever his ties with the magazines’ publisher, American Media Inc. He said: "The governor of the state of California makes some important decisions every day. Today, he has to make a decision about a conflict of interest - his own."

But a spokesman for the governor defended the arrangement, saying Mr Schwarzenegger has had dealings with the magazines for more than three decades. "There is no technical conflict," Rob Stutzman said.

Mr Stutzman added that Mr Schwarzenegger had been a proponent of dietary supplements since his days as a bodybuilder.

The contract between Weider Publications, a subsidiary of American Media, states that Mr Schwarzenegger will receive 1 percent of the magazines’ advertising revenue each year for five years.

Although an arrangement with the publisher had previously been made public, the amount involved had not. The contract stipulates that it will be no less than $1 million a year but could reach much higher.

The governor does not accept his $175,000 annual salary from the state, instead taking a nominal $1 salary.

Last year, the magazines also agreed to donate $250,000 a year to the California Governor’s Council on Physical Fitness.

American Media Inc publishes a number of leading supermarket tabloids in the US, including the National Enquirer, the Globe and the Star - which regularly ran salacious stories about Mr Schwarzenegger's private life before he declared he was running for governor.

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