JAKARTA (Bloomberg) - Japan's ruling Liberal Democratic Party is set for a rule change that may allow Prime Minister Shinzo Abe to remain in office until after the 2020 Tokyo Olympics.

Party lawmakers accepted on Wednesday (Oct 26) a proposal by LDP Vice President Masahiko Komura to permit party leaders to serve three consecutive three-year terms - a change that would become official after a party convention in March.

Under the current regulations, Abe would be forced to step down in 2018, six years after taking over as party leader.

In Japan, the leader of the ruling party is nearly always voted in as prime minister by parliament. Abe has led the LDP to four straight national election victories, and maintains solid support rates that have eluded his recent predecessors.

While his economic policies have had mixed success, rivals in the party have not gathered much support and the main opposition party has yet to offer a credible alternative, even under a high-profile new leader.

The LDP's favoured candidates won two by-elections at the weekend, bolstering speculation that Abe will call another general election early next year to cement his position until 2021.

The change could see Abe serving as prime minister for almost nine years - longer than anyone since World War II - assuming the party continues to win elections and he opts only to stay on through the Olympics. The LDP itself has been in power for the vast majority of the past 60 years.