TOKYO (Reuters) - Japanese Finance Minister Yoshihiko Noda said on Saturday Tokyo would take decisive steps to stem the yens rise when needed, while suggesting that coordinated currency market intervention was a difficult option. Traders are getting cautious about bidding the yen up too much after Japanese ministers kept up warnings against the currencys surge to 15-year high versus the dollar. Policymakers have repeatedly said they could take decisive action on the yen normally a code phrase for currency intervention. Prime Minister Naoto Kan and ruling party powerbroker Ichiro Ozawa are facing off in a ruling party leadership vote on September 14 that is distracting policymakers as Japan confronts a strong yen and weak economy. The winner will likely be prime minister by virtue of the partys majority in the powerful lower house. Kan and Noda have said Japan would take decisive action on currencies without using the word intervention. But Ozawa has more specifically threatened to intervene in the currency market. What they (Kan and Ozawa) have been saying means the same thing. The issue is whether we would actually decide to intervene at the end, Noda said on a Tokyo television programme. Our statement that we would take decisive steps when needed says it all, he added. Despite repeated warnings, traders have doubts over whether Tokyo will step into the forex market now because it could have trouble convincing leaders of other major economies about the need to intervene at a time when they are calling on China to make the yuan more flexible to ease global imbalances. They say the United States and European countries seem to have no interest in helping Japan by jointly intervening in the market to curb the yens rise as they want to benefit from falls in their currencies, which boost exports. Asked about the perception that coordination with other countries on the yens rise seem to be tough, Noda said, Its about what we can do while coordination is difficult.