Azarov, who is on a two-day visit to Brussels, said his country was not seeking any "discount" or "privileged quotas" for imported Russian gas, but insisted that the current agreement, signed by his predecessor Yulia Tymoshenko, was unfair.
Ukraine and Russia signed a 10-year agreement on gas supplies in January 2009 after a price dispute between the two neighbours left the European Union without fuel for two weeks amid freezing temperatures.
"Russia doesn't want to revise [the gas agreement]. Why? Because it's profitable for them. Why do we want to revise it? Because we believe this is an ill-profitable agreement for us," Azarov said.
"How much time should an agreement live for, if one party sees it as profitable, and the other as highly unprofitable? Something needs to be done with this agreement. Quite obviously, it is not viable."
The Ukrainian prime minister also spoke against the planned South Stream gas pipeline project, led by Gazprom, which is designed to bypass his country.
"We tell Russia that Ukraine is a reliable transit country for Russian gas in whatever direction you wish. We have traditional pipeline routes [like] Pomary–Urengoy–Uzhgorod. We are ready to upgrade our southern capacity and access the same city of Burgas in Bulgaria, which South Stream has as its objective via an offshore pipeline under the Black Sea," Azarov said.
Azarov's visit was largely seen as preparation for the EU-Ukraine Summit on 22 November. During his time in Brussels, the prime minister repeated that his country's objective remained European integration but said Kiev would not apply for EU membership before planned reforms had created the right conditions.
"The most important thing for us is to do ourselves the work necessary to bring Ukraine closer to European standards. We view this as a process. Step by step, we will get closer to the way of life of the EU and European standards," Azarov said.
As a first step, he expressed hope that Ukraine would sign a free trade agreement with the EU during the first half of 2011.
Azarov added he saw no conflict between developing relations with the EU and with Russia. "We are calm and confident negotiators. And we have the same stance with Russia and with the EU," he said.
Azarov rejected allegations that his country was returning to an authoritarian state model following recent constitutional reform. Responding to a question from EurActiv on press freedom, he said he was "not making a tragedy from the fact that from time to time tendentious articles appear". Such articles, he said, were "obviously commissioned" by the government's political opponents.