The United States government plans to stockpile vaccines, limit international and domestic flights, quarantine those who become ill and bring in the military to maintain order if a flu pandemic strikes the country.

The federal government's $7.1 billion national plan released Wednesday, however, doesn't call for a closure of its borders if a pandemic such as the feared human bird flu strain developed.

The government said a super-strain influenza pandemic would cause massive disruptions that would last for months, and states, cities and businesses must make plans now to keep functioning -- and not count on federal aid.

"Local communities will have to address the medical and nonmedical impacts of the pandemic with available resources," the report warns, saying the federal government won't be able to offer the kind of money expected after hurricanes or other one-time natural disasters.

The plan predicts as many as two million Americans could die if a pandemic were to evolve, and as many as 40 per cent of workers would be off the job for several weeks.

The plan lists more than 300 recommendations including:

• People in the workplace should stay three feet apart and avoid face-to-face contact;
• College and university dorms would be used to quarantine the sick;
• Infected people should voluntarily quarantine themselves, and quarantine would be mandatory in the most extreme cases; and
• Flight crews should have facemasks on board to put on coughing travellers.

Homeland Security advisor Frances Townsend described the plan as a road map that outlines which government agency is responsible for the more than 300 tasks in the event of a pandemic.

She said a human bird flu strain has not begun, and noted only 205 people overseas have fallen sick from the Asian bird flu, called the H5N1 strain.

About half of those people have died.

If a deadly strain mutated, Townsend said the government would take immediate action by mobilizing response teams, implementing measures to restrict movement across its borders and work with international bodies to deal with the pandemic.

"I should make clear from the outset that we do not know if the bird virus we are seeing overseas will ever become ... a pandemic," Townsend told reporters at a news conference.

"(But if that happens) we will take immediate action to prevent or to slow the spread of the infection."

President George Bush's administration concludes closing its borders would do little to stop the spread of a flu pandemic because they escalate too quickly and before symptoms appear.

Townsend denied suggestions that were a pandemic to strike the U.S., it would create chaos.

"Good planning and preparation will prevent it from being chaotic," she said.

"It will not be a single moment-in-time event. It will unfold slowly over days, weeks, months; it will not be in all places at the same time. There's good news to that," Townsend added.

With files from The Associated Press