* Noda says competitive currency devaluation on G20 agenda
* Policymakers failed to reach conclusion on FX at G7
* Brazil has warned currency war threatens global economy (Adds to Noda quote)
By Stanley White
TOKYO, Oct 13 (Reuters) - Japanese Finance Minister Yoshihiko Noda said on Wednesday that South Korea's leadership of the Group of 20 nations forum could come under question due to its regular currency market intervention.
Noda, speaking to lawmakers in parliament, also said he could not answer whether or not the government will conduct currency intervention as the yen hovers near a 15-year high versus the dollar.
Noda drew a distinction between Japan's currency intervention last month, which appears so far to have been a one-off move, and more frequent intervention by South Korea and China.
But this is unlikely to discourage criticism of Japan's intervention as leaders struggle to reach a consensus on the global currency system to prevent competitive currency devaluation from damaging economic growth.
"As chair of the G20, South Korea's role will be seriously questioned," Noda said when asked about South Korea's currency intervention and its place in G20.
"In South Korea, intervention happens regularly, and in China, the pace of yuan reform has been slow. Our message is that we have confirmed at the Group of Seven that emerging market countries with current account surpluses should allow their currencies to be more flexible."
The dollar fell 0.5 percent to 81.72 yen, not far from a 15-year low of 81.37 struck on Monday on electronic trading platform EBS.
Japan sold 2.1 trillion yen ($25.65 billion) last month in its first currency intervention in more than six years to curtail the yen's strength against the dollar.
Finance ministers will meet in South Korea for a G20 summit from Oct. 22. (Editing by Chris Gallagher)