Iranian President Mahmoud Ahmadinejad dismissed the oil minister and two other ministers on Saturday, news agency ISNA reported.

'Ministers of oil, social welfare and industries and mines were dismissed by President Mahmoud Ahmadinejad in order to slim down the government's ministries from 21 to 17,' Isna said.

A shake-up of the department in charge of the world's fifth- biggest oil exporter, was expected after some officials said earlier this month that the oil and energy ministries and labour and social welfare ministries would be merged.

No announcement was made about who will take over any new merged protfolios. Parliament would have to approve the remit of any new ministry.

Getting approval from parliament, whose speaker Ali Larijani has publicly criticised Ahmadinejad's domestic and economic policies, will not be easy.

Iran's top authority Supreme Leader Ayatollah Ali Khamenei has a discretion over key ministries, including oil, foreign, intelligence and interior.-Reuters