RIYADH, Sept 27 (Reuters) - A Saudi woman has been named to a senior government post for the first time, authorities said on Wednesday shortly after a ban on women drivers was lifted as the conservative kingdom takes steps to modernise its image.

Saudi Arabia, the birthplace of Islam, had been widely criticised for being the only country in the world that barred female motorists, a tradition seen by rights activists as emblematic of Riyadh's repression of women.

Twenty-four hours after King Salman issued a decree end the ban, the government announced that a woman had been appointed as assistant mayor of Al Khubar governorate.

Eman Al-Ghamidi was given the post "as part of plan to boost the number of females in leadership positions in line with Vision 2030", the Center for International Communication at the Ministry of Culture and Information said in a statement.

The Saudi government has said Vision 2030, a vast plan of economic and social reforms, will raise women's share of the labour market to 30 percent from 22 percent currently.

Saudi women rejoiced at their historic new freedom to drive on Wednesday, with some taking to the roads even though licences will not be issued for another nine months.

Letting women drive could eventually raise pressure to remove other obstacles to their employment, such as a male guardianship system that requires women to have a male relative's approval for most decisions on education, employment, marriage, travel plans and even medical treatment.

(Reporting by Stephen Kalin; editing by Mark Heinrich)