TOKYO—Prime Minister Shinzo Abe is hoping to get some help from his Group of Seven friends this week for his plans to prop up Japan's economy with more government spending.

The meeting of leaders from seven major industrialized nations, taking place Thursday and Friday in Ise-Shima, Japan, comes at a critical time for Mr. Abe. Growth in the first quarter was better than expected, but the economy is struggling to gather sustained momentum, even after the Bank of Japan introduced negative interest rates early this year.

Mr. Abe faces parliamentary elections in July and a decision on whether to postpone a sales-tax increase scheduled for April 2017. He is also considering a government spending package.

His advisers said they are hoping the G-7 leaders, including President Barack Obama, will endorse using government purses to stimulate growth world-wide. That might help win over skeptics in Japan.

"The only way to grow the economy when private consumption and investment are stalling is through government expenditures," Finance Minister Taro Aso said Friday.

Faced with risks to the world economy, global policy-makers have stressed the need in recent months to take a more balanced approach to stoking growth, by adding more fiscal spending and structural reforms to the extraordinarily easy monetary policy already in place.

Efforts by Japan and others to reach consensus on the need for more government spending, perhaps in coordination, ran into skepticism from Germany during a meeting of G-7 finance ministers last weekend. Germany stressed the need to reduce deficits and debt while undertaking structural reforms, and the ministers ended up concluding that each country should take the measures it deems appropriate.

Advisers said Mr. Abe plans to try again, seeing German Chancellor Angela Merkel as possibly more willing to make a concession on wording than her finance minister, fiscal hawk Wolfgang Schä uble.

Once the meeting is over, Mr. Abe will quickly turn his attention to domestic politics. The current session of parliament is set to end June 1. A senior administration aide said Tuesday that Mr. Abe would hold a news conference that day and may declare his intention on the national sales-tax, which is set to rise to 10% from 8% in April 2017.

The aide said Mr. Abe was considering delaying the tax increase. While Ministry of Finance officials have pushed for the increase to happen on schedule, citing the need to repair Japan's finances, the aide said the prime minister didn't trust their views and feared a repeat of April 2014, when an earlier tax rise pushed Japan's economy into recession.

Consumer spending has yet to fully recover from that tax increase, and the economy has since alternated between minor expansions and contractions. The volatility has undermined business confidence and made it hard to plan for capital investment.

The planned tax increase is part of efforts to safeguard Japan's social security system and reduce the government's debt burden, which is among the world's biggest. Mr. Abe has already delayed the increase once, vowing that it would go ahead next year unless there is an economic shock on par with the global financial crisis.

The aide also said there was a chance Mr. Abe would call a snap election for parliament's more powerful lower-house to coincide with the upper house vote in July. The lower house election needn't be held until December 2018, but calling it now, while Mr. Abe remains fairly popular, could enable him to extend his mandate while providing political cover for delaying the tax rise.

Yet even some lawmakers who supported an earlier delay in raising the sales tax now say the increase should proceed as scheduled. A group of them recently recommended to Mr. Abe that he permit it to go ahead while asking the Bank of Japan to finance additional government spending, which would help offset the impact of the tax increase.

"The economy won't get better simply by announcing a delay" in the tax increase, said a statement from the group, led by lawmaker Kozo Yamamoto, a member of Mr. Abe's Liberal Democratic Party and one of the architects of his growth program.

Some of Mr. Abe's advisers have called for a spending package of up to 10 trillion Japanese yen. They include Satoshi Fujii, a Kyoto University professor, who said it should include an infrastructure program aimed at dispersing the administrative and business functions of Tokyo to other parts of Japan to mitigate the impact of natural disasters.

"Defeating deflation through growth is the best pathway to fiscal sustainability," Mr. Fujii said in a recent interview.

Write to Mitsuru Obe at mitsuru.obe@wsj.com and Peter Landers at peter.landers@wsj.com

(END) Dow Jones Newswires

May 24, 2016 04:55 ET (08:55 GMT)