* Spokesman says minister working tirelessly on Germany's behalf

* Media reaction underlines German unease over Greek bailout

By Erik Kirschbaum

BERLIN, Feb 29 (Reuters) - German Finance Minister Wolfgang Schaeuble was criticised on Wednesday for playing Sudoku on a small computer during a crucial parliamentary debate on Greece, becoming a lightning rod for the growing opposition in Germany to the latest bailout.

His spokesman defended Schaeuble against charges of arrogance for playing the numbers puzzle while on the government bench during the debate, saying he had worked tirelessly for 10 straight days on behalf of German interests.

Schaeuble has been one of the most popular members of Chancellor Angela Merkel's government for his no-nonsense style and his tight grip on spending, but his arm-twisting of lawmakers in his party to support Greece has made him more vulnerable to attacks.

An opinion poll in Bild am Sonntag on Sunday found Germans, who are making the largest contribution to the euro zone bailout for Athens, overwhelmingly oppose further aid to Greece.

German public broadcaster ARD first aired pictures on Monday evening of a smiling Schaeuble appearing to play Sudoku on his partly concealed computer while a member of the centre-right coalition spoke in favour of the second Greek rescue package.

"Caught! The Finance Minister was apparently playing Sudoku during the debate," ARD said. Schaeuble's spokesman Martin Kotthaus said the network later apologised for airing the close-up of Schaeuble's computer, a violation of parliament rules.

Bild newspaper attacked Schaeuble for not paying attention during the debate on the bailout in a story headlined: "During the 130 billion euro debate in parliament it was - of all people - Finance Minister Schaeuble who was playing Sudoku."

In an accompanying editorial "You've got quite some nerve, Herr Schaeuble!", the country's best-selling daily said: "With all due respect Herr Minister, that was out of line, over the top and arrogant.

Conservative daily Die Welt defended Schaeuble, who has been known to play Sudoku at European Union meetings.

"He got caught by photographers playing a numbers game during the debate - so what?" Die Welt wrote. "He surely read all the files before breakfast and he already knows his colleagues' arguments. Why not train the brain instead?"

Merkel's centre-right coalition could not muster a majority of its own in the vote for the second bailout for Greece but the measure passed with the help of opposition Social Democrats and Greens.

Kotthaus said on Wednesday he did not want to comment on the incident but then said he and Schaeuble had worked for about 10 straight days without rest before Monday's debate in parliament.

"I find your question a bit curious," Kotthaus told a government news conference when asked what Schaeuble was doing during the debate. "If you look back at the last 10 days, we've been working more or less non-stop since last Monday on Greece, Greece (rescue) 2, the ESM, the EFSF and other issues."

(Reporting By Erik Kirschbaum, editing by Gareth Jones and Tim Pearce)

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