A panel of doctors in Japan's Nuclear Regulation Authority says iodine tablets should be distributed in advance to residents under 40 to mitigate the effects of radiation exposure due to a nuclear accident.
The panel compiled the proposal on Friday.
Iodine tablets are used to prevent the thyroid gland storing radiation.
World Health Organization guidelines say iodine tablets should be distributed to children and pregnant women first because they may face high risks of thyroid cancer after radiation exposure in a nuclear accident.
Iodine tablets are distributed mainly to residents within five kilometers of nuclear plants. But actual distribution is very slow, making it urgent to put children first.
The panel proposes that in principle iodine tablets should be distributed in advance to people under 40 as well as pregnant women and lactating mothers.
It also says people aged 40 or over can ask for the tablets if there are sufficient supplies, even though it has not been proved that cases of thyroid cancer due to radiation exposure will increase among this age group.
The team also says in an emergency tablets should be distributed regardless of age.
The authority says it hopes to use the proposal to review the guidelines for distribution to help speed it up.