TOKYO (REUTERS) - Japanese actor-turned-politician Taro Yamamoto is angling for a new real-life role in which he leads his novice party and allies to victory, ousts long-ruling conservatives and takes over as premier within the next few years.

Whether or not he can achieve that ambitious target, Mr Yamamoto says his tiny Reiwa Shinsengumi party - which elected two seriously disabled candidates to Parliament's Upper House this month - is already having an impact.

"Our two lawmakers have not entered Parliament yet, but already they are making (the chamber) barrier free," he told Reuters in an interview.

"Even if we are smaller than the number two opposition party, I think we can have a big impact."

Political experts agree Reiwa - named after the new imperial era that began in May - can have an impact on policies and attitudes, such as regarding the disabled, but achieving the longer-term goal would be a long shot and might well require merging with other groups.

Reiwa was set up three months before the July 21 Upper House poll. It joined a fragmented opposition camp with a platform heavy on policies aimed at those who remain socially marginalised and economically struggling despite almost seven years of Prime Minister Shinzo Abe's "Abenomics" policies to revive growth.

The group's use of social media and the T-shirt clad Mr Yamamoto's charismatic stump speeches won him the largest number of votes of any single candidate in the proportional representation portion of the election.

Under a priority candidate system, that propelled the two disabled people to victory even though Mr Yamamoto lost his own seat.

Mr Yamamoto, 44, now plans to run 100 candidates - including himself - in a Lower House election that must be held before late 2021 and is likely, he says, to come within a year.

"I'm saying I'm going to take power, so first I have to run for the Lower House," he said, adding that he wanted to be prime minister but wouldn't insist if someone else could do the job.

By cooperating with other opposition parties, he aims to expand their presence in the Lower House, defeat Mr Abe's ruling bloc in a 2022 Upper House poll and take power in the following lower house election.

'MISERABLE LIVES'

"People's livelihoods will only become more miserable," Mr Yamamoto said, predicting the economy would worsen after a planned October sales tax rise to 10 per cent from 8 per cent.

"As long as we don't change our direction, our momentum will continue."

Mr Yamamoto said his priority for inter-party cooperation was agreeing to cut the sales tax to at least 5 per cent in order to relieve the burden on the less-well-off and boost consumption.

His call to abolish the levy has sparked criticism that his policies are fiscally unrealistic. Agreeing to reduce it could be a high hurdle for parties like the biggest opposition Constitutional Democratic Party of Japan, which has called for freezing the tax at its current level.

Many economists say a higher sales tax is vital to fund the bulging social security costs of Japan's ageing population.

Japan has had a flurry of opposition parties since the Democratic Party of Japan ousted the Liberal Democratic Party in 2009 and began a troubled three-year reign that ended when Mr Abe took power in December 2012.

The fragmentation has kept many dissatisfied with the ruling bloc from voting. Turnout fell below 50 per cent in the Upper House poll for the first time since 1995.

Mr Yamamoto admitted the low turnout was a hurdle for his party, which lacks an organised base.

"Only a small percentage of the people are grasping control, so to take back control, it's necessary to have flexible ties with people who don't vote," he said.

"It's hard to convince them that they are connected to politics."