PORTLAND — Oregonians and people across the country need to take the possibility of a flu pandemic seriously and prepare for a possible outbreak, a top Bush administration official and Oregon’s governor said Thursday.

“We’re overdue for a pandemic and under-prepared,’’ Mike Leavitt, secretary of the U.S. Department of Health and Human Services, told more than 100 government, health and business representatives at an influenza planning summit.

At the meeting, state and federal officials sharpened their plans to deal with a potential global influenza problem in Oregon. If a pandemic occurs, government officials are prepared to detect and attempt to control it but said the total impact would be beyond their reach.

An influenza pandemic could cripple the work force, economy and well-being of the state. So, officials recommend all citizens, community groups and businesses also make plans to cope.

“People of Oregon will have to come to the help of people of Oregon,’’ said Leavitt, whose agency is holding influenza pandemic preparedness summits in every state.

A flu pandemic occurs when a new virus emerges that can be passed easily and rapidly among people across the globe. Because it is new, people would have no natural immunity and it could cause a more serious problem than a normal seasonal flu.

If a moderate flu pandemic occurred, about 1 million Oregonians could become ill, 12,000 could require hospitalization and 3,000 could die, the state public health department said.

There has not been an influenza pandemic since 1968 and the odds are low that the current avian flu strain will mutate to one passed easily among humans, said Susan Allan, Oregon’s public health director.

If an influenza pandemic did occur, hospital and health systems could be short of staff and equipment to care for all patients, forcing some to ration care. The public health system would be able to communicate in real-time with hospitals and other first responders but might not be able to address all community needs.

“We seem to live in increasingly troubled times,’’ Gov. Ted Kulongoski said. “Strangely though, Americans are not worried about influenza.’’

“We in Oregon are not prepared for a pandemic,’’ Kulongoski said.

On the Net: Department of Health and Human Services pandemic flu information: http://www.pandemicflu.gov/