FOREX-Dollar gains before Yellen's testimony, euro falls

* Dollar firms ahead of Fed chair's appearance before Senate panel

* Euro slips on lingering Greece worries, business data miss

* Swiss franc the main loser from Friday's Greek loan extension

* Greece to submit planned reforms Tuesday, misses deadline (Recasts after Greece misses deadline, adds graphic link)

By Richard Leong

NEW YORK, Feb 23 (Reuters) - The dollar rose on Monday against most currencies as investors await clues from Tuesday's testimony from U.S. Federal Reserve Chair Janet Yellen before a Senate panel on the timing of a possible interest rate increase.

The euro retreated on lingering doubts over whether Greece's four-month bailout extension struck late Friday would lead to a deal to keep Athens solvent. A somewhat disappointing private report on German business confidence spurred further selling in the single currency, analysts said.

"The Greece debt deal has been mildly positive, but it's difficult to determine what is the next move yet before Yellen's testimony tomorrow," said Lane Newman, director of foreign exchange at ING Capital Markets in New York.

The index of the dollar against a group of six currencies was up 0.3 percent at 94.565 after touching 94.915, its highest level in more than a week.

While traders have been expecting the Fed would eventually end the near-zero interest rate policy it adopted in December 2008, weak domestic inflation and a sluggish global economy have complicated such a move, analysts said.

Recent domestic data, including home resales fall to a nine-month low in January, suggested some deceleration in the U.S. economic expansion, making it tougher for the Fed normalize interest rates as early as this summer.

Worries about Greece and what Yellen might say before the Senate Banking Committee at 10 a.m. (1500 GMT) on Tuesday helped lift the yen against the euro and dollar .

Among other major currencies, the Swiss franc lost nearly 1 percent against the dollar to near five-week lows as some of the safety flows waned on the conditional loan extension to Greece.

Greece will present its economic reform plans on Tuesday to seal a eurozone financial lifeline, missing a Monday deadline.

Also weighing on the euro was the Ifo report that showed that while German business optimism edged up to a seven-month high in February, the reading fell short of economists' forecasts.

The euro was down 0.4 percent at $1.1336 and down 0.5 percent at 134.75 yen, according to the EBS trading system.

The dollar dipped 0.1 percent against the yen, last traded at 118.88 yen.

The Swiss franc was down 1.3 percent at 0.95125 franc per dollar, while the euro was up 0.9 percent at 1.07835 francs, not far from a five-week high of 1.08115 struck late on Friday. (Additional reporting by Anirban Nag in London; Editing by Toby Chopra and Nick Zieminski)