An embassy official said such an agreement had been reached during a meeting between the Belarusian and Russian presidents on March 19 in Moscow.
Russian Ambassador to Minsk Alexander Surikov said in February the price of Russian natural gas for Belarus would average $150 per 1,000 cu m in 2009, adding that everything would depend on crude and oil derivatives prices.
Belarusian First Deputy Prime Minister Vladimir Semashko previously said the average gas price for Belarus was expected to be $148 per 1,000 cu m, but with oil prices falling below $50 per barrel, gas prices could be lower than the 2008 level ($128 per 1,000 cu m).
Belarus earlier requested that Russia cut gas prices due to the falling oil price on global markets.
However, Russian energy giant Gazprom denied on Friday that any agreement had been reached on an "average" price for gas deliveries in 2009 or that the price would be linked to world oil prices.