In the four months since winning the Democratic Party of Japan presidential election, Prime Minister Yoshihiko Noda has survived by taking a cautious approach to governing, managing to compile the 2012 budget and several bills to finance restoration of the disaster-hit Tohoku region.

But 2012 will be a rocky year for Noda, observers say. In the divided Diet, where the opposition controls the Upper House, Noda will struggle to pass several key bills that will see him seeking cooperation from opposition parties while dealing with recalcitrant members of his own party.

"He made fewer enemies compared with (former Prime Minister Naoto) Kan, but it doesn't mean that rebuilding his dwindling support rate and realizing policies will become any easier" this year, said Koichi Nakano, a political science professor at Sophia University.