TOKYO (REUTERS) - Japanese Chief Cabinet Secretary Yoshihide Suga, a longtime loyal aide of outgoing Prime Minister Shinzo Abe, was poised to win a ruling party leadership election on Monday (Sept 14), virtually ensuring that he replaces Abe this week in the nation's top job.

Suga, 71, who has said he would pursue Abe's key economic and foreign policies, is expected to get the bulk of votes from 394 Liberal Democratic Party (LDP) lawmakers and is likely to win a majority of 141 votes from the party's local chapters.

Suga was on track to win over 70 per cent of the MPs' votes and was leading among local chapters, public broadcaster NHK reported.

The winner of the LDP race is virtually certain to be elected prime minister in a parliamentary vote on Wednesday because of the LDP's majority in the lower house. He will serve out Abe's term as party leader through September 2021.

Abe, Japan's longest serving premier, said last month he would quit due to ill health, ending a nearly eight-year term.

Suga has said he would continue Abe's signature "Abenomics" strategy of hyper-easy monetary policy, government spending and reforms while juggling the challenges of Covid-19 and a slumping economy, and confronting longer-term issues such as Japan's ageing population and low birthrate.

Suga, whose resume is thin on diplomatic experience, faces geopolitical challenges such as building ties with the winner of the Nov 3 US presidential election and balancing concern over China's maritime aggressiveness with bilateral economic interdependence.

Speculation is simmering that Suga will call a snap election for parliament's lower house as soon as next month to boost his chances of winning a full three-year term as LDP chief next year. A vote for the lower chamber must be held by late October 2021.

Suga, the son of a strawberry farmer from northern Japan who got his start in politics as a local assemblyman, has since 2012 held the key post of chief cabinet secretary, acting as Abe's top government spokesman, coordinating policies and keeping bureaucrats in line.

He has the image as more of a behind-the-scenes operator than a frontline leader but rose in opinion polls after he announced his candidacy to succeed Abe.

He won support from most LDP factions, outpacing his rivals, former defence minister Shigeru Ishiba and ex-foreign minister Fumio Kishida.