TOKYO — Japanese Finance Minister Taro Aso won’t attend a gathering of global economic leaders in Argentina next week, according to people familiar with the matter, costing him the chance to push back against US tariffs and voice his views on currencies.

Mr. Aso, who is facing calls to resign after his ministry doctored files at the center of a cronyism scandal, will be represented by a deputy at the March 19-20 meeting of Group of 20 (G-20) finance ministers and central bankers in Buenos Aires, said to two ruling coalition lawmakers with knowledge of plans. Bank of Japan Governor Haruhiko Kuroda is expected to attend.

Vice Finance Minister Minoru Kihara will go instead of Mr. Aso, said the lawmakers, who declined to be named because there hasn’t been an official announcement. Masatsugu Asakawa, the chief of foreign-exchange policy, will also attend. A spokesman for the finance ministry declined to comment.

As finance minister and deputy prime minister, Mr. Aso leads all economic discussions with the US, overseas Japan’s currency policy and is also head of the agency regulating cryptocurrencies, which will be hot topic at this meeting. His absence at the G-20 will weaken Japan’s voice as other nations seek to resist US protectionism.

“This comes at a bad time,” said Masaaki Kanno, chief economist at Sony Financial Holdings, Inc. “If he can’t go to G-20, that could cost not only the government but also the Japanese economy.”

The scandal stems from the sale of land to an educational institution with ties to Prime Minister Shinzo Abe and his wife, and the finance ministry’s subsequent tampering with documents. While Messrs. Aso and Abe have both denied any wrongdoing, the prime minister’s approval ratings have taken a turn for the worse.

While policy makers in Tokyo have been relatively quiet on the currency recently, there is some concern about the yen’s appreciation, which hurts exporters and undermines effort to push inflation higher. The yen has gained about 6% against the dollar this year. — Bloomberg