Dozens of people have protested outside the Belarussian embassy in Moscow over the ongoing detention of opposition figures in Minsk.
At least five presidential candidates and 14 other activists are in pre-trial custody following demonstrations against President Lukashenko's disputed re-election.
Prosecutors in Belarus say protest leaders could face up to 15 years in jail.
Last week nearly 600 protesters were jailed for up to a fortnight.
"We're here because not all is well in Belarus, the neighbouring country we love. Because there are people under arrest there. Because you need to celebrate New Year not in jail but at home with your children," said protester Victoria Igrieva, a journalist with the Russian newspaper Novaya Gazeta.
Lukashenko's victory brought an estimated 10,000 people onto the streets, protesting that the vote was rigged. Western countries agreed and the EU is reviewing its relations with Belarus.
There have also been unsubstantiated claims that state provocateurs were behind violence that gave the police an excuse to suppress the demonstration.
But Russian monitors backed the result and Lukashenko vowed there would be no more "senseless democracy".