Vyacheslav Volodin, the speaker of the Duma, said the Russian lower house of parliament was preparing a law to introduce higher taxation for people who have left the country, as many have since the war in Ukraine began in February.
"It is right to cancel preferences for those who have left the Russian Federation and to introduce an increased tax rate for them," Volodin wrote on the Telegram messaging app.
"We are working on appropriate changes to the legislation."
The number of Russians who have left since the start of the war is unclear.
By early October, some local media had reported that as many as 700,000 had fled following the September announcement of a mobilisation drive to call up as many as 300,000 to fight. The government rejected that figure at the time.
Russia's 13% personal income tax is deducted automatically by domestic employers. Russians working abroad who are Russian tax residents must pay the tax independently, according to the Federal Tax Service of Russia.
"It's completely understandable why they fled," Volodin said. "Those who realized that they had made a mistake have already returned. The rest should understand: the vast majority of society does not support their act and believes that they betrayed their country, relatives and friends."
(Reporting in Melbourne by Lidia Kelly; Editing by Bradley Perrett)