MANILA - The replacement for resigned Department of Foreign Affairs (DFA) Secretary Albert del Rosario will be announced in due course, the department's spokesperson said Tuesday.

"As to the secretary's replacement, I think a formal announcement will be made in due course," DFA Assistant Secretary Charles Jose told reporters.

The 76-year-old Del Rosario, citing health reasons, tendered his resignation effective March 7, 2016.

"Having served our country for over 10 years, I have respectfully asked the President if I could be allowed to step down earlier than midyear due to health issues," del Rosario said Monday.

Del Rosario was on the board of one of Manila's largest mining firms, which has a stake in oil exploration in the West Philippine Sea, when President Benigno Aquino III appointed him as foreign affairs secretary in 2011.

He also served as ambassador to the United States under the Arroyo government.

Del Rosario led the Philippines' effort to file an arbitration case in the Hague, questioning China's claims in the West Philippine Sea, in a case Beijing has not recognized.

The Philippines, Brunei, Malaysia, Taiwan and Vietnam also have claims on the sea, believed to have huge deposits of oil and gas. About $5 trillion of ship-borne trade also passes through the waterway every year.

The arbitration court's decision is expected in May or June. - With a report from Reuters