NEW YORK U.S. Treasury Secretary Janet Yellen said on Tuesday whether Washington would show understanding over another yen-buying intervention by Japan "depends on the details" of the situation.

"We usually communicate with them about these interventions and generally understand the need to smooth out following undue volatility, but not to attempt to influence the level of exchange rates," Yellen said, when asked whether the United States would show similar understanding as it did last year when Japan intervened in the currency market to stem sharp yen falls.

"So it depends very much on the details in our discussions with the Japanese," she told reporters on the sidelines of a climate finance event in New York.

Japan made rare forays into the currency market to prop up the yen in September and October last year to stem a plunge in the currency that eventually hit a 32-year low of 151.94 to the dollar.

While the yen is still well off that low, many market players see 150 as Tokyo's line-in-the-sand which, if breached, could trigger another round of intervention. The dollar stood around 147.74 yen in Asia on Wednesday.

While a weak yen gives Japanese exporters' profits a boost, it hurts households and retailers by boosting the cost of importing raw material and fuel.

(Reporting by David Lawder in Washington; Writing by Leika Kihara in Tokyo; Editing by Stephen Coates)