“Russian authorities recently confirmed that foreign citizens with permanent residency or a multiple-entry visa can be sent back by bus,” Norwegian police said in a statement.
Some 5,500 migrants — mostly from Syria, Afghanistan, Iraq and Iran — crossed last year from Russia into Norway, on the last leg of an arduous journey through the Arctic to Europe.
Norway is not within the European Union, but is a member of the Schengen passport-free zone.
In November, the country's right-wing government decided that migrants who had been living legally in Russia, or entered Russia legally, should be immediately returned there, on the basis that Russia is a safe country.
Since then the police had been quietly putting migrants on bicycles back across the Storskog border crossing, 400 kilometres (about 250 miles) north of the Arctic Circle.
Bicycles became the preferred mode of transport of migrants seeking to cross into Norway, because Russian authorities do not let people cross the border on foot and Norway considers people driving migrants across the border in a car or truck as human traffickers.
NGOs had expressed outrage at the migrants being forced to retrace their steps on two wheels in winter, when temperatures in the region regularly fall to -20C (-4F).
“It's much better to return people with Russian residency permits in a dignified manner,” Jon Ole Martinsen of the Norwegian Organization for Asylum (NOAS) said.
The police were unable to confirm the number of people expelled by bicycle, saying only a total of 371 people had been returned to Russia last year.
“They were given bicycles at the border… In many cases, they used them to carry their bags and pushed them 200 or 300 metres” to the Russian side of the border, Daniel Drageset, a spokesman for the immigration police, told AFP, assuring they were “adequately dressed” for the weather.