* Dollar rises as ADP jobs data shows surprise strength

* Fed extends liquidity-boosting measures

* Euro-zone economic sentiment at lowest since March 2003 (Recasts, updates prices)

By Lucia Mutikani

NEW YORK, July 30 (Reuters) - The dollar rose broadly on Wednesday as data showed an unexpected jobs gain in the U.S. private sector raised prospects of a less steep decline in nonfarm payrolls on Friday and investors snapped up stocks.

Steps by the Federal Reserve, the European Central Bank and their Swiss counterpart to extend liquidity offers to stressed financial instutions also contributed to positive sentiment towards the greenback, analysts said.

Poor euro-zone sentiment data, which provided further evidence of rapidly deteriorating economic conditions, helped to lift the dollar index to a one-month high for the second straight session.

"The ADP (employment report) number is bullish for the U.S. dollar, especially in an environment where we've seen in the last few weeks U.S. data surprising on the upside," said Matthew Strauss, senior currency strategist at RBC Capital Markets in Toronto.

"One should be reminded that the ADP number is not a highly reliable indicator of what might happen to nonfarm payrolls. But nonetheless it has increased the risk that nonfarm payrolls could be much stronger than the minus 75,000 expected."