"As such, the government must take all available means" to cushion the economic blow from U.S. tariffs, such as offering funding support for domestic firms and taking measures to protect jobs, Ishiba told parliament.

Ishiba said Trump's decision to slap tariffs on imports from Japan was "extremely disappointing and regrettable," adding that Japan will continue to explain that it had done nothing unfair to the United States.

Ishiba also said he was willing to visit the United States for a meeting with Trump as soon as possible. "But in doing so, we must ready a package of steps on what Japan could do," he added.

Trump's decision to slap a 25% levy on auto imports, and a reciprocal 24% tariff on other Japanese goods, is expected to deal a huge blow to Japan's export-heavy economy with analysts predicting the higher duties could knock up to 0.8% off economic growth.

Fears of a global recession have also led to steep declines in stock prices worldwide including Japan's Nikkei share average, which tumbled nearly 9% early on Monday.

Ishiba summoned key economic ministers, including Finance Minister Katsunobu Kato, Sunday evening and instructed them to be vigilant and "respond appropriately" to market developments, according to Japan's Nikkei newspaper.