* EU officials believe Chinese yuan still undervalued
* Juncker says forex interventions should be coordinated
(Updates with EU Commission official, background)
LUXEMBOURG, Sept 17 (Reuters) - Top European Union officials are expected to press China's prime minister and central bank governor next month to deliver on the country's promise to make its exchange rate more flexible.
The 16-nation euro zone and the wider EU believe the Chinese yuan currency is undervalued, which they believe helps create global economic imbalances and at times gives the country's exporters an unfair advantage, officials say.
Eurogroup chairman Jean-Claude Juncker said on Friday he would meet the two Chinese policy makers on Oct. 6 in Brussels to discuss exchange rate issues and monetary policy.
"I will have a meeting with the Chinese prime minister and central bank governor on Oct. 6 ... to discuss monetary issues and exchange rate problems," Juncker, who chairs monthly meetings of euro area finance ministers, told reporters.
The 27-country EU welcomed China's declaration in June that its foreign exchange rules would be made more flexible, but stressed that implementation was key.
"Since then, progress has been, let's say, slow," a Commission official told Reuters, asking not to be named.
During their visit, Premier Wen Jiabao and central bank chief Zhou Xiaochuan are also expected to meet European Commission President Jose Manuel Barroso and EU Monetary Affairs Commissioner Olli Rehn.
Juncker also reiterated his opposition to Japan's decision this week to intervene unilaterally to weaken the yen currency.
"We think that unilateral initiatives are not the best way to deal with the problem," he said.
On Thursday, Juncker said that the Chinese yuan currency was still undervalued against the euro and that Europe had to press harder for this to change.
"We have to discuss more formally and with more insistence with our Chinese counterparts the elements related directly to foreign exchange rates. We do think that the yuan, the renminbi, is still undervalued," he said after a meeting of EU leaders. (Reporting by Michele Sinner; writing by Marcin Grajewski and Charlie Dunmore; Editing by Ron Askew)