Japan's [Images] outgoing prime minister Shinzo Abe [Images] was admitted to hospital Thursday morning, a day he resigned.

Doctors said Abe was suffering from severe exhaustion related to stress and would remain hospitalised at least three to four days, according to wire reports.

Abe on Wednesday announced his resignation, ending a year-old government plagued with scams and an electoral defeat.

"I am determined today to step down," a visibly emotional Abe said at a hurriedly-arranged press meet in Tokyo. Fifty-two-year-old Abe said that he had decided to resign as it would be difficult for him to regain public trust to implement key policies.

Abe said he even reshuffled the cabinet in order to push forward certain reforms but under the current situation it has become difficult for him to secure people's support and trust to implement policies. His controversial policies include providing refueling support to the US-led operations in Afghanistan.

However, analysts were surprised by Abe's decision as he had refused to quit earlier in spite of strong pressure over the ruling coalition's heavy defeat in the upper house elections in July, a spate of resignations by ministers and scandals involving key members of his administration.

Abe, who took office on September 26 last year, said it will be better if he steps down and a new prime minister pursues a fresh law for the extension of the refueling mission as well as other key policy matters.      

Chief Cabinet Secretary Kaoru Yosano said Abe's health was also a reason behind the move, saying the premier has been distressed trying to balance his duties and physical state.

Yosano declined to discuss the specifics of Abe's health problem but said that the premier's condition had deteriorated, especially after his three-nation Asia visit, which included India, in late August.

Image: Shinzo Abe announcing his resignation at a press conference on Wednesday. Photograph: Toru Yamanaka/AFP/Getty Images