A leading Chinese expert on Japanese affairs is predicting a gradual improvement in relations between Asia's two biggest economies after this Sunday's Upper House election, regardless of Prime Minister Shinzo Abe's hawkish political beliefs.

"It is welcoming for China that there will be political stability," Yang Bojiang, a deputy director of the Institute of Japanese Studies at the Chinese Academy of Social Sciences, said, predicting Abe's ruling Liberal Democratic Party and junior coalition partner New Komeito will win a majority in the poll.

Yang said in a recent interview that he expects Abe to make no compromises on the sovereignty of a group of islets in the East China Sea known as the Senkaku in Japan and Diaoyu in China. But at the same time, Yang said, "whether he likes or not," Abe is likely to come under pressure from the private sector and a range of other quarters to water down the current difficult situation after the election.