* Newly-appointed party leader Rinne is former union boss
* Rinne wants new stimulus, but party has limited power
* Finnish economy dropped back to recession, debt grows
(Adds Rinne's views on ECB, quotes, analyst comment)
By Jussi Rosendahl
HELSINKI, May 28 (Reuters) - Finland's Social Democrats on Wednesday named Antti Rinne, a former union boss and critic of the government's austerity measures, as the country's new finance minister and deputy prime minister.
Rinne, 51, replaces Jutta Urpilainen, whom he narrowly beat in a party vote earlier this month to oust her as party chair. Urpilainen then announced she was stepping down as finance minister in the five-party coalition government.
A former leader of the country's biggest white-collar workers union, Rinne is known for feisty negotiation tactics, as well as favouring a large role for the state in boosting economic growth. He has never been elected to parliament.
The ministerial change, due to take effect next week, comes as the country's triple-A-rated economy is struggling. The coalition is due to hold talks next month regarding its last year in office.
Rinne repeated he would seek new stimulus measures, even though analysts said falling support for the party has weakened his hand.
"From the SDP's viewpoint it is important that economic growth and employment become priorities in these negotiations," he told reporters. "We have a brutal number of unemployed people, it is very important to address this issue."
Support for the Social Democrats, the second biggest party in the coalition, has waned fast. The party won only 12.3 percent of the vote in Sunday's elections to the EU parliament, falling to fourth place.
"I think the SDP has rather small chances for any major changes. They don't want early elections with this kind of support, so they have basically nothing to threaten the coalition partners with," said politics professor Kimmo Gronlund from Abo Akademi University.
Adjusted unemployment in the Nordic country was at 8.5 percent in April, equalling a four-year high, but still well below the euro zone average of 11.8 percent.
Finland's economy fell back into recession in the first three months of 2014 amid trouble at its key industries and weak private consumption.
TRIPLE-A RATINGS
Credit rating agencies are keeping a close eye on government debt, with Standard & Poor's saying this month that "any substantial moves to derail policies aiming at addressing the government's medium-term fiscal position" might lead to a rating cut.
Rinne has also recently said he aims to discuss with the government a change in the European Central Bank's mandate. He wants to allow the ECB to directly buy government bonds to moderate debt yields. He would also add employment and growth as a new ECB monetary policy target.
Urpilainen was known for taking a hard line on euro zone bailouts and demanding collateral for loans. Rinne instead said he would cut interest rates and lengthen maturities on Greece's loans to help the troubled economy grow.
The country's prime minister is also due to change soon as the conservative National Coalition Party will choose its new leader at a party congress on June 14.
Finland's next general election is scheduled for April 2015.
(Reporting By Jussi Rosendahl, editing by Alister Doyle)
((jussi.rosendahl@thomsonreuters.com)(+358 9 6805 0248)(Reuters Messaging: jussi.rosendahl.thomsonreuters.com@reuters.net))
Keywords: FINLAND FINANCEMINISTER/
