HOUSTON — While the Obama administration is stressing the need to diversify America’s fuel supplies and wean the nation from its dependence on foreign oil, Saudi Arabia, the world’s biggest oil exporter, is warning about a “nightmare scenario” if consumers seek to speed up the development of alternative fuels.

Ali al-Naimi, the Saudi oil minister, said Tuesday evening at an oil industry conference in Houston that a push to develop more renewable fuels might jeopardize investments in conventional fuels.

“While the push for alternatives is important, we must also be mindful that efforts to rapidly promote alternatives could have a chilling effect on investment in the oil sector,” he said. “A nightmare scenario would be created if alternative energy supplies fail to meet overly optimistic expectations, while traditional energy suppliers scale back investment due to expectations of declining demand for their products.”

Saudi Arabia, along with other oil exporters, has long complained about what they view as the uncertainty of energy policies in Western nations. This uncertainty, oil producers argue, hampers their ability to make long-term plans to develop their resources.

Mr. Naimi’s comments came as the new administration considers ways to diversify the nation’s fuel supplies and reduce oil consumption. The United States is the world’s top oil consumer.

At the moment, the slowing economy and collapsing demand for oil is freezing investments around the world. The secretary-general of the Organization of the Petroleum Exporting Countries said recently that cartel members had canceled 35 drilling projects because of lower prices.

Over the past five years, Saudi Arabia has been spending billions to significantly increase its production capacity. By the end of 2009, it will be able to pump 12.5 billion million barrels a day, up from around 9 million barrels a day just a few years ago.

Mr. Naimi said that the expected growth in energy demand over the coming years meant that more supplies will be needed in future years.

He also stressed the need for consumers to be more efficient in their energy needs. Renewable fuels also have a place, he said. But he cautioned that the scale of the energy system was so large that, so far, only oil can meet the world’s thirst for energy.

“Over time, the world will likely transition away from the current fossil fuel-based energy economy,” Mr. Naimi said. “However, we don’t yet know which fuels or technologies will emerge on the path ahead. Nor can we accurately predict how long this transition will take. Recognizing the inherent uncertainty in the process of transition to new forms of energy, we must pursue an ‘inclusive’ energy strategy.”

Mr. Naimi said that all forms of energy are required to meet the needs of a growing global population and the aspirations of billions of people in developing countries for greater prosperity.

“All B.T.U.’s are welcome and needed — whether they come from renewable energy, nuclear power or fossil fuels,” he said.