TOKYO (Reuters) -Japan's top currency diplomat Masato Kanda said on Tuesday that authorities were ready to deal with foreign exchange matters "24 hours", while declining again to comment on whether the finance ministry had intervened to prop up the yen a day earlier.

"Whether it's London, New York or Wellington (hours), it doesn't make a difference," the vice finance minister for international affairs told reporters a day after the dollar tumbled to a low of 154.40 yen from as high as 160.245 in what traders cited as intervention.

Kanda reiterated that the government would continue taking appropriate action when needed and respond to foreign exchange moves in accordance with rules set under international frameworks such as the Group of Seven advanced countries and International Monetary Fund.

Japan's currency surged as much as five yen against the dollar on Monday after the currency hit fresh 34-year lows earlier in the day.

The Wall Street Journal reported that Japanese financial authorities had intervened in the market, citing people familiar with the matter.

Kanda on Monday declined to comment when asked by reporters whether authorities intervened in the currency market, but said the current developments in the currency market were "speculative, rapid and abnormal" and could not be overlooked.