Saudi Arabia's stock market fell sharply on Wednesday after Saudi state television reported that King Abdullah had been admitted to hospital for tests.

The main equities index, which was down more than 1 per cent earlier in the day in response to sliding oil prices, was 5.0 per cent lower in the minutes after the television report, which quoted a brief royal court statement.

The report said King Abdullah is undergoing medical tests at  King Abdulaziz Medical City of National Guard in Riyadh. There were no further details.

King Abdullah was born in the early 1920s. The softly-spoken monarch, who took power in 2005 after the death of King Fahd, has undergone surgery in the past few years related to a herniated disc.

State media last week reported that King Abdullah had left Riyadh for his desert farm at Rawdat Khuraim northeast of the capital. - Reuters