MOSCOW — A senior member of the Russian government opened a rare public breach with the Kremlin on Sunday, saying he would refuse to stay on under the leadership shuffle that was announced over the weekend, in which the president and prime minister will change places.

The official, Aleksei L. Kudrin, Russia’s long-serving finance minister, said he would no longer work in the government if President Dmitri A. Medvedev became prime minister, citing what he said were irresponsible spending decisions by Mr. Medvedev.

Mr. Kudrin’s remarks were the first to suggest that the leadership swap announced Saturday, which sent a ripple of surprise among senior ministers, could lead to turmoil and a reorganization at the highest levels of government.

Several Russian officials said Sunday that they had no warning of the decision that Vladimir V. Putin planned to return as president after elections in March, which he is likely to win, and appoint Mr. Medvedev as prime minister, despite Mr. Putin’s assertion on Saturday that that deal had been sealed “several years ago.”