Japanese Prime Minister Yoshihide Suga will pull out of a party leadership race in September, officials said, setting the stage for his replacement after just one year in office. Mr Suga, who took over after Shinzo Abe resigned last September, citing ill health, has seen his support ratings sink to below 30 per cent as Japan struggles with its worst wave of Covid-19 infections ahead of a general election this year. Ruling Liberal Democratic Party officials said Mr Suga would finish his term as its president, meaning he would stay on until his successor is chosen in party-wide election slated for September 29. The winner of the contest is all but assured of being premier because of the LDP's majority in the lower house. The government has been considering holding the general election on October 17. "Honestly, I'm surprised," said LDP secretary general Toshihiro Nikai, who had declared his support for Mr Suga as party leader. Mr Suga was planning to reshuffle his cabinet and party executives, but those plans were no longer valid, Mr Nikai said. Fumio Kishida, a former foreign minister, is competing for the LDP leadership. On Thursday, he criticised Mr Suga's coronavirus response and called for a stimulus package to combat the pandemic. "Kishida is the top runner for the time being but that doesn't mean his victory is assured," said Koichi Nakano, political science professor at Sophia University. Mr Nakano said the popular Administrative Reform Minister, Taro Kono, could run if he received the backing of his faction leader, Finance Minister Taro Aso, while former defence minister Shigeru Ishiba could also run but looks at a disadvantage. Unlike last year, grassroots LDP members will vote along with the party's members of parliament, which makes the outcome of the leadership race harder to predict. Novice MPs, fearful of losing their seats, may be wary of following their elders' orders. Mr Suga's image as a savvy political operator capable of pushing through reforms and taking on the stodgy bureaucracy propelled his support to 74 per cent when he took office. Initially, populist promises such as lower mobile phone rates and insurance for fertility treatments were applauded. But removing scholars critical of the government from an advisory panel and compromising with a junior coalition partner on policy for healthcare costs for the elderly drew criticism. His delay in halting the "Go To" domestic travel programme – which experts say may have helped spread coronavirus in Japan – hit hard, while the public grew weary of states of emergency that hurt businesses.