Japan's ruling party has elected Finance Minister Yoshihiko Noda as its new leader, meaning the fiscal conservative will almost certainly become the nation's sixth prime minister in the last five years.

Democratic Party of Japan legislators chose Noda over Trade and Industry Minister Banri Kaieda in a two-man runoff Monday. Parliament is expected to elect him as prime minister Tuesday.

Noda immediately acknowledged the challenges he faces, from righting a troubled economy to cleaning up the aftermath of the Fukushima nuclear disaster.

Noda is expected to try to form a coalition with the opposition Liberal Democratic Party and a third party, but it is not clear whether the LDP will be willing to cooperate.

Former foreign minister Seiji Maehara had been considered as the Japanese public's favorite among the five candidates for DPJ leader. However, he ran third in Monday's first round of balloting and was eliminated.

Outgoing Prime Minister Naoto Kan resigned Friday, fulfilling a promise he made earlier this year.

Mr. Kan's public approval rating had slumped amid widespread frustration with the government's handling of the disaster at the Fukushima Daichi nuclear power plant.

The new prime minister will face enormous challenges as Japan struggles to recover from the March 11 earthquake and tsunami and bring the nuclear power plant under control. More than 20,000 people are dead or missing from the twin disasters and thousands more have been displaced from homes near the Fukushima plant.

Across Japan, homes and factories are operating on reduced power as the government conducts safety tests on all of the country's nuclear reactors.

The new prime minister will also have to deal with a deeply divided parliament. While the DPJ has a solid majority in the lower house, the upper house is in the hands of the opposition Liberal Democratic Party and in a position to block any legislation.