The arrest of dozens of Saudi royal figures, ministers and businessmen is just the start of an anti-corruption drive, the attorney general says.

Sheikh Saud al-Mojeb issued a statement describing the detentions as "merely the start of a vital process to root out corruption wherever it exists".

News of a major purge of Saudi Arabia's business and political leadership emerged on Sunday.

It is seen as bolstering the power of Crown Prince Mohammed bin Salman.