By Megumi Fujikawa

TOKYO--Japan's Finance Minister fired off yet another verbal warning to currency speculators, reaffirming her readiness to take action to prop up the yen.

"Our stance remains unchanged. We stand ready to take appropriate action at any time as needed," Satsuki Katayama said at a press conference Friday.

The latest in a string of warnings by Japanese officials comes as markets stay on alert for potential government intervention in the foreign-exchange market, with some seeing the U.S. holiday weekend as a possible window of opportunity when liquidity thins.

Katayama said Tokyo is in close contact with Washington, regardless of the July 4 holiday. The two sides remain steadfast in sticking to their previous agreement that foreign-exchange intervention can be considered to combat excess market volatility and disorderly movements, she added.

The yen recovered some ground overnight against the dollar, following the release of weaker-than-expected U.S. jobs data, and got a further lift from Katayama's remarks. The dollar fell to around 160.90 yen after she spoke, before returning above the 161 level.

Even with the brief leg up, the yen is trading near historic lows against the dollar, threatening to accelerate imported inflation and raise households' living costs. A persistently weak yen has amplified Japan's cost-push inflation, squeezing real wages as the surging costs of imported energy and food outpace domestic income gains.

Write to Megumi Fujikawa at megumi.fujikawa@wsj.com