* Greek package triggers broad buying in euro
* Investors still cautious and seeking clarity
* Net short yen positions highest since October 2007 (Updates prices, adds detail)
NEW YORK, April 12 (Reuters) - The euro rose to its highest against the dollar in nearly a month on Monday after euro zone finance ministers agreed on a rescue package for Greece, though the currency pared its gains as investors sought details.
The ministers approved a 30 billion euro ($40.5 billion) aid package of loans, which Greece could tap if needed, with at least 10 billion euros also expected from the International Monetary Fund. For more, please see [ID:nLDE63A0BO]
The massive financial safety net boosted investor appetite for riskier assets, briefly helping the Australian dollar to its highest in five months.
Investors then became more cautious, prompted in part by the need for clarification of details on how the aid mechanism could be activated.
Christoph Steegmans, a German government spokesman, said on Monday that euro zone leaders, not those of the full European Union, would need to meet to activate the aid package for debt-ridden Greece. [ID:nBAT005290].
Earlier, Steegmans had said such a decision would require a full meeting of EU leaders. But when asked by Reuters to clarify the point, he said a meeting "of government leaders from euro zone countries" would be needed.
Early headlines said the German Bundestag would also need to be consulted. [ID:nBAT005288]
"All attention so far is on the news from Greece," said John Doyle, foreign exchange strategist at Tempus Consulting in Washington. "It shows stabilization on the euro on just the offer from the European Union."
But there are worries about the role of the International Monetary Fund, Doyle said.
"It shows that the euro zone can't take care of one its own," he said. "The worry is, it would be a larger amount for a bigger EU economy."
The euro rose as high as $1.3691
It was last up 0.8 percent on the day at $1.3606 midway through the New York session, closer to the session low of $1.3565 than the session peak, according to Reuters data.
Against the yen, the single currency earlier rose more than
1 percent to 127.45 yen
Greek borrowing costs eased, driving the premium investors pay to hold 10-year benchmark Greek debt rather than German paper to 353 basis points from Friday's 409 bps.
Greece will test market appetite for its debt further with an auction of 1.2 billion euros of Treasury bills on Tuesday [ID:nLDE6380B3].
The single currency is still down 5 percent against the dollar and 4.6 against the yen in 2010 to date, making it one of the biggest underperformers among major currencies this year.
"The EU deal should get Greece past the April and May refunding hump but beyond that the outlook still looks grim as the economy sets course for a sharp contraction. Participants still have good reason to tread cautiously versus the euro," Lloyds TSB said in a note to clients.
Greece needs to roll over 3.85 billion euros of maturing bills this month and refinance 8.2 billion euros of a five-year bond maturing later in April.
The high-yielding Australian dollar briefly rose as high as
$0.9382
The dollar rose 0.2 percent against the yen to 93.31 yen
Net short yen positions rose to the highest since the week ended Oct. 9, 2007, according to Commodity Futures Trading Commission data released on Friday. [ID:nN09152191].
"Japan cannot sustain a strong yen at this point," said Sacha Tihanyi, currency strategist at Scotia Capital in Toronto. "On a relative outlook, the Bank of Japan will be among the last to tighten" interest rates. (Additional reporting by Natsuko Waki in London) (Reporting by Nick Olivari; Editing by Dan Grebler)