Sergei Lavrov, the Russian foreign minister, made his comments on Wednesday as Vladimir Putin, the Russian president, held talks with Chinese leaders in Beijing.
The talks were mainly on energy but also addressed Iran's nuclear stand-off with the West.
Lavrov said: "I think our efforts should focus on preventing the NPT system from being destroyed.
"We think the NPT system should be improved. We [Russia and China] share a common view on most international issues ... to use multilateral co-operation to reach agreement all parties can accept."
The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) is a 1970 global pact against the spread of atomic weapons which is policed by the International Atomic Energy Agency (IAEA) in Vienna.
Russia, backed by China, has held up an agreement on a draft statement the UN Security Council could issue telling Iran to stop atomic research, which Western powers say is a cover for pursuing weapons.
Iran says its nuclear programme is peaceful.
Russia and China are wary of action by the Security Council, which can impose sanctions, fearing that threats may prompt Iran to cut off contact with the IAEA.
A spokesman for the Chinese foreign ministry, Qin Gang, said on Tuesday that China supported a Russian compromise proposal that would allow Iran to use nuclear fuel enriched in an internationally monitored plant on Russian soil, easing fears that Tehran could divert atomic material to develop weapons.