UPDATE 1-Martinsa Fadesa asks creditors for waiver on loan

(Adds details, trader, share price)

MADRID, July 11 (Reuters) - Spanish property company Martinsa Fadesa (MFAD.MC) on Friday said it had asked creditor banks to waive until August 7 a requirement for it to obtain a loan for 150 million euros as part of a refinancing agreement.

In a regulatory filing, the company added that it had asked for the waiver because the deadline for obtaining the loan had expired.

The company's shares plunged on the news, and by 0842 GMT were down 7.16 percent at 13.61 euros, while the Madrid bourse's benchmark index was up 0.25 percent .IBEX.

"This is very bad news. It puts the refinancing deal at risk, and that is obviously weighing on the share price," a dealer said.

At the beginning of May Martinsa Fadesa said it had closed a deal to refinance 4 billion euros of debt -- out of a total of 5.1 billion -- and postpone the biggest payments until 2011.

Spain's decade-long property boom has recently ended and is weighing on the wider economy, where growth has fallen from one of the fastest rates in Europe last year to 0.3 percent in the first quarter. (Reporting by Carlos Ruano; Writing by Martin Roberts, editing by Will Waterman)