"I think it is by no means a good idea," Dirk Fischer, transport policy spokesman for the conservative Christian Democrats (CDU), told the newspaper Berliner Zeitung.
Fischer, an MP from Hamburg, said Russian interest could be grounded in political and strategic goals and that allowing Russia to buy into the rail carrier could be risky because of the political situation in Moscow.
"They want to enter our market also because of the transport routes," he said, suggesting that Germany should first seek partners and investment from other European Union members.
Fischer admitted, however, that the German parliament will have little influence on who invests in the Deutsche Bahn. Parliamentary approval is expected later this month for partial privatization of the Deutsche Bahn under a plan approved by Germany's ruling parliamentary coalition of the CDU, their Bavarian sister party the Christian Socialists (CSU) and centre-left Social Democrats in late April.
Private investors will be able to invest in up to 24.9 percent of the rail unit involved in freight and passenger traffic. Deutsche Bahn's 34,000 kilometre (21,127 miles) network of tracks, train stations and energy supplies will remain in public ownership.
Vladimir Yakunin, president of RZD Russian railways, expressed interest in Russian investment in the Deutsche Bahn on Wednesday during an international transport conference in the southern Russian city of Sochi.
"This is a good idea, and we have discussed it with (Bahn chief executive) Hartmut Mehdorn," Yakunin said.