"The invitations to the international observers will be sent out tomorrow," Vladimir Churov said, adding that the observers would total up to 400.
The announcement by the Central Election Commission came after repeated speculation that Russia wanted to limit the number of observers at the elections to just 50.
The team of monitors will come from the Parliamentary Assembly of the Council of Europe, the Organization for Security and Cooperation in Europe (OSCE), the Commonwealth of Independent States, the Shanghai Cooperation Organization, and the Nordic Council.
Churov also said representatives of election commissions from the United Kingdom, France, Germany, Italy and Jordan would likewise be invited to monitor the elections to the 450-seat Russian State Duma.
The number of observers is still lower, however, than at the 2003 parliamentary elections, when the OSCE alone was represented by some 400 observers on polling day.
A total of eleven parties will run for the lower house of Russia's parliament, the Central Election Commission said on Sunday.
President Putin earlier said he would head the list of the main pro-Kremlin party United Russia at the elections, and that he could become prime minister in 2008 if the party gains a majority.
The decision has widely been seen as a bid to hang onto power upon the expiration of his second, and under the Russian Constitution, final term as president. Analysts had speculated that Putin would seek to strengthen the role of the prime minister, weakening the president's powers.
However, speaking after the 20th EU-Russia summit last week, Putin denied that he had any such plans. "If anyone thinks I am planning to make a move to the government and transfer fundamental powers there, this is not so. Russian presidential powers will not be reduced, as long as this is down to me," Putin told a news conference after the 20th EU-Russia summit.
Also speaking after the summit, Portugal's prime minister, Jose Socrates, said the European Union was pleased with Moscow's plans to invite OSCE observers to the December parliamentary polls.
"The EU is pleased with what President Putin said about plans to invite OSCE observers to upcoming elections in Russia. This is important news, this is something that will enhance confidence between the parties," the premier said.
