In an election-year speech on Wednesday, Bush proposed what amounts to a limit on the number of nations allowed to produce nuclear fuel.
The policy seeks to prevent the use of civilian nuclear technology to enrich uranium as it could also be used for making weapons.
Bush has been on the defensive in recent weeks over the failure to find weapons of mass destruction in Iraq and his approval ratings have been dropping.
But his speech at the National Defence University offered a chance to seize the high ground and emphasise his re-election campaign theme of strengthening national security.
The president spoke at length about the case of Pakistani nuclear scientist Abd al-Qadir Khan, the father of Pakistan's atomic bomb, who confessed last week to leaking nuclear secrets to Libya, North Korea and Iran.
Bush also cited the Khan case as a victory for US intelligence, after weeks of pounding over intelligence flaws in Iraq.
National security adviser Condoleezza Rice told NBC's "Today" show that Bush planned to ask "the international community to become more serious about this very vexing problem for international politics".
Nuclear suppliers group
Bush called on the Nuclear Suppliers Group - the 40 nations that sell most nuclear technology - to refuse to sell equipment to any country not already equipped to make nuclear fuel.
US officials believe nuclear programmes in Iran and North Korea have exposed gaps in the nuclear Non-Proliferation Treaty and will call for tougher action by the International Atomic Energy Agency to prevent a repeat of their example.
Ashton Carter, who was an assistant defence secretary during the Clinton administration, said Bush's proposals could be helpful.
"If the United States can manage the diplomatic job of making this proposal a reality, it will be a major step forward in stopping nuclear proliferation and preventing nuclear terrorism," he said.