DUBAI, May 4 (Reuters) - Saudi Arabian home prices tumbled by nearly 10 percent from a year ago in the first quarter because of pressure on the economy from low oil prices and government austerity measures, official data showed on Thursday.

Residential real estate prices sank 9.5 percent in the January-March quarter, according to the General Authority for Statistics' Real Estate Price Index. The decline accelerated from a 7.3 percent drop in the fourth quarter of last year.

Last month, the government said that in order to stimulate economic growth, it was restoring financial allowances for civil servants that were cut last September to save money. But other austerity steps are expected in coming months, so this may not provide much support to home prices.

Commercial real estate prices plunged 11.7 percent from a year earlier in the first quarter, the authority said.

(Reporting by Andrew Torchia, editing by Pritha Sarkar) ((andrew.torchia@thomsonreuters.com; +9715 6681 7277; Reuters Messaging: andrew.torchia.thomsonreuters.com@reuters.net))