Russian MPs are set to debate and vote on a bill extending the presidential term - amid speculation it could herald the early return of Vladimir Putin, reported BBC.
Parliament, dominated by Putin allies, is considering the bill, announced only last week by President Dmitry Medvedev.
Mr Putin became prime minister this year after being obliged under the constitution to step down after two consecutive presidential terms.
But speculation is rife that he is planning to return to the presidency.
The BBC's Richard Galpin says it has always been assumed that Mr Putin might return after Mr Medvedev has completed one term.
But the apparent rush to get this measure through - it was announced for the first time last week and is being accelerated through parliament - is being seen by some as a sign that Mr Putin is in a hurry, and may return much sooner.
Then, he could potentially serve another two six year terms.
The process of ratification is due to continue into next week.
The bill must go before the upper house of parliament and regional assemblies before it becomes law.
There is no doubt the bill will be approved quickly as the Kremlin's party, United Russia, controls all the assemblies.
The government insists the reform will only apply to the next president and it is needed because the existing four-year term is too short to implement serious reforms in such a huge country but the next election is not due until 2012.
One political analyst told the BBC that Mr Putin, who stood down as president in May, could now be planning to come back well before the next election and wants a longer term in office.
The word is that Mr Putin wants to be able to deal with the financial crisis which is beginning to hit Russia very hard, our correspondent reports.