"We shall help Irina in collecting signatures. I have already given instructions to our 80 regional organisations to start this work," Nemtsov said on Monday.
According to him, this is the collegiate decision of the SPS leadership.
The co-chairwoman of the SPS, Irina Khakamada, has nominated herself for the presidency. The SPS and another liberal party, Yabloko, have decided not to nominate their candidates for the presidential elections on March 14.
The day before, Irina Khakamada said on the Ekho Moskvy radio station that she would ask the leaders of the liberal parties for help because of the difficult procedure to collect two million signatures necessary for self-nominees and the candidates from the parties which were not elected to the parliament. The signatures must be presented to the Central Election Commission of the Russian Federation before January 28.
"The decision about a political support of Irina will be taken by the congress, and I would not like to foretell its decision," said Nemtsov.
The SPS congress has been scheduled for January 24.
The position of Yabloko has not yet been known.