By Masayuki Kitano

TOKYO, Sept 30 (Reuters) - Japanese authorities conducted atotal of 2.1249 trillion yen ($25.37 billion) in currencyintervention in the latest month to Sept. 28, the Ministry ofFinance said on Thursday.

That was roughly in line with market estimates for about 2trillion yen ($23.9 billion) in intervention on Sept. 15, theonly confirmed instance of Japanese currency intervention duringthat span.

"This number was pretty much in line with what the market hadbeen talking about," said Ian Stannard, senior currencystrategist at BNP Paribas in London.

Finance Minister Yoshihiko Noda confirmed that Tokyo hadunleashed its first foreign exchange intervention in six years onSept. 15, when the dollar hit a 15-year low of 82.87 yen.

"With regard to future intervention, I think what will drivethem is whether dollar/yen equals its 15-year lows or breaksbelow that level," Stannard said.

"Right now, a lot of corporate flows are pushing up the yenand that will happen regardless of monetary policy. It will be atough job to go against the momentum."

If confirmed that the monthly figure all took place on Sept.15, that will beat the previous record of 1.666 trillion yen forJapanese yen-selling intervention on a single day set on Jan. 9,2004.

The MOF will announce details such as specific interventiondates and currency breakdowns when it unveils its July-Septemberintervention data, expected in early November.

The dollar has been under selling pressure on speculation theFederal Reserve will take more quantitative easing steps laterthis year to shore up the U.S. economy.

That has driven the yen higher, which has acted as a drag onJapanese exports and raised concerns in Tokyo that it couldderail a fragile economic recovery and exacerbate deflation.

The dollar was trading at 83.30 yen on Thursday, less thanhalf a yen above its 15-year low. It leapt 3 yen on Sept. 15 to85.78, when the authorities intervened throughout the Asian,European and U.S. trading day.

The Bank of Japan intervenes on behalf of the Ministry ofFinance and traders said Sept. 15 was also probably the firsttime it had conducted intervention by directly placing orders onelectronic trading platform EBS.

The dollar also spiked last Friday on rumours of furtherintervention but there was no confirmation Japan had intervened,and the dollar lost all its gains by the end of the day. Moneymarket data later showed it was unlikely and Prime Minister NaotoKan also said that day he was unaware of any new intervention.

Before Sept. 15, Japan had not intervened in the foreignexchange market since March 2004, when it ended a 15-month, 35trillion yen selling spree aimed at preventing a strong yen fromsnuffing out an economic recovery. (Additional reporting by Charlotte Cooper and the London forexteam; Editing by Chris Gallagher)