"Woodside has maintained normal drilling operations except for a minor disruption due to delays in freight movements," Chinguetti operator Woodside said in a statement.

"All of Woodside's staff and contractors have been accounted for and are safe. The company will continue to monitor the situation."

Woodside's joint venture partners include Australian companies Hardman Resources and Roc Oil, as well as UK companies BG Group and Premier Group. Perth-based junior Baraka petroleum has permits in onshore Mauritania.

Troops in the north-west African country took power yesterday while President Maaouyia Ould Taya was He in Saudi Arabia for the funeral of King Fahd.

The new junta, which calls itself the Military Council for Justice and Democracy is led by Mauritania's director of national security, colonel Ely Ould Mohammed Vall. It has said it will usher in a democracy within two years.

President Ould Taya is himself a former army chief of staff who seized control of Mauritania in a bloodless coup in 1984. On his way home when news of the coup reached him, Ould Taya was forced to land in the neighbouring state of Niger.

Mauritania's oil industry is in its infancy, but Woodside and its joint venture partners have made substantial finds offshore.

At 10.15am AEST, Woodside shares were at $30.04, down 1.5% on yesterday's close of $30.50.

Roc was down 3.4%, hitting $2.31, down from yesterday's close of $2.39.

Hardman was particularly hard hit, falling 15 cents or 6% from yesterday's close, to hit $2.34.