Currency stability is "extremely important," and Japan's government would examine the economic impact from the foreign exchange moves, said Finance Minister Shunichi Suzuki, as the yen fell to its lowest level since late 2018.

Before the minister's remarks on Friday, the dollar surged to a near 3-year high against the yen at 113.885 yen, partly on anticipation that inflation risks will prompt the US Federal Reserve to hike interest rates sooner than expected.

Later on Friday, the dollar reached 114.075 yen for the first time since December 2018.

"Currency stability is crucial.  We will continue to closely monitor currency market moves and their effects on the economy," said Suzuki.

“Though a weaker yen increases import costs for some firms and consumers, it helps exporters.”

Japanese policymakers usually issue verbal warnings against unwelcome yen increases, which could jeopardise the world's 3rd-largest economy, which is export-reliant.

September saw Japan's wholesale inflation reach a 13-year high as rising global commodity prices and a weak yen increased import costs, putting pressure on corporate margins and increasing the risk of undesired consumer price hikes.

"I was quite surprised by the minister's comment, which gave the impression that he was concerned a weak yen," said chief forex strategist at Mizuho Securities, Masafumi Yamamoto.

"He probably wanted to convey to consumers that a weak yen doesn't make everything better, as he needed to show sympathy towards consumers facing increased import costs ahead of the elections. However, that no one in the market expected the government to respond to the yen moves at this point via measures such as yen-buying intervention.”

Japan has refrained from currency market intervention since 2011, when damaging earthquakes and subsequent Fukushima nuclear crisis were followed by a spike in a safe-haven yen.

Rising fuel costs, according to Economy Minister Daishiro Yamagiwa, will "certainly" impact Japan's resource-deficient economy. Yamagiwa refused to comment on the weak yen’s economic consequences, as commenting on currencies in his capacity would be “problematic.”