DUBAI, July 27 (Reuters) - Saudi Basic Industries Corp 2010.SE (SABIC), one of the world's largest petrochemicals groups, reported a 23.2 percent drop in second-quarter net profit on Wednesday, extending a earnings slump as lower sales prices continued to weigh.

SABIC made a net profit of 4.74 billion riyals ($1.26 billion) in the three months to June 30, down from 6.17 billion riyals in the year-earlier period, the company said in a bourse statement.

The result was ahead though of the 3.92 billion riyal average estimate of five analysts polled by Reuters.

SABIC, which is 70 percent state-owned, attributed the profit fall to lower average sales prices, in addition to an impairment on the assets of Ibn Rushd, an affiliate of SABIC.

Lower oil prices have adversely affected SABIC's earnings, with the company's profits falling in the seven preceding quarters, Reuters data shows.

The company's results are closely tied to oil prices and global economic growth because its products -- plastics, fertilisers and metals -- are used extensively in construction, agriculture, industry and the manufacturing of consumer goods.

Saudi's petrochemical companies, which for years benefited from subsidised gas feedstock prices versus competitors from non-energy producing countries, are also having to adjust to government energy and gas feedstock reforms which will raise their costs.

From the first quarter of 2016, SABIC's total annual costs before minority interests will rise by around 5 percent.

($1 = 3.7503 riyals)

(Reporting by Hadeel Al Sayegh; Editing by David French) ((Hadeel.AlSayegh@thomsonreuters.com; +971566883310;))