A nuclear cooperation agreement between Russia and Australia went into force on Thursday after their two leaders exchanged notes to ratify the deal.
Under the agreement Australia will sell uranium to Russia, against the advice of an Australian parliamentary committee.
Legislators had called for the deal to be blocked unless Russia met a number of conditions, including speeding up reforms to separate civilian and military nuclear plants.
"To open a new page, we have a good event today, an exchange of ratification notes," Russian President Dmitry Medvedev told Australian Prime Minister Julia Gillard at a meeting before the opening of the G20 summit in Seoul.
The agreement, which allows Australian uranium to be enriched in Russia and used in Russian nuclear reactors, was signed in Sydney in 2007 and ratified by the lower house of Russia's parliament this summer.
It last for 30 years but can remain in force indefinitely if there are no objections from either side. The agreement means uranium supplied to Russia can be used only for peaceful purposes, must meet International Atomic Energy Agency safeguards and can be used only in facilities agreed by Australia.
A previous agreement signed in 1990 specified that Australian uranium supplied to Russia could be enriched for use by third countries only.