Over the next two years, an estimated 297 million oral polio vaccines and $35 million no longer needed for polio-free regions will be redirected to the 13 countries, the World Health Organization, U.N. Children's Fund, U.S. Centers for Disease Control and Prevention and Rotary International said in a joint statement.
The shift in resources was partly caused by the scarcity of funds.
"We are having difficulty with financing, so we had to prioritize," said UNICEF Japan program coordinator Yasushi Katsuma.
Officials predict the eradication program will cost $275 million from the end of 2002 through 2005, and said they expect a $33 million shortfall this year alone.
Once an epidemic, the disease has disappeared from much of the planet.
Last year, polio affected 1,919 people and was endemic in only seven countries: Afghanistan, Egypt, India, Nigeria, Niger, Pakistan and Somalia.
Six other countries - Angola, Bangladesh, the Republic of Congo, Ethiopia, Nepal and Sudan - have no reported cases but remain at high risk of infection because of their proximity to polio-ravaged areas and lower rates of vaccinations, UNICEF's Katsuma said.
Among the infected countries, India, Pakistan and Nigeria account for 99 percent of all cases, the WHO said.
The last major disease to be successfully eradicated under a WHO-sponsored vaccination program was smallpox, which saw its last case in 1978.
To be declared disease-free, a country must have no new cases for three years.
Polio attacks the central nervous system, causing paralysis and, occasionally, death. It is transmitted through food or water contaminated by the feces of an infected person. There is no cure.
By Kenji Hall