No one who enters the country on a visit or tourist visa is allowed to work in the UAE. However, those people who want to work in the UAE temporarily can apply for a mission visa.
This visa is issued for 180 days and can be renewed for a further 180 days.
The initial cost is AED 1,800 and the renewal is AED 1,200.
To apply for this visa, you must first obtain a temporary work permit from the Ministry of Labour (http://www.mol.gov.ae/indexEng.aspx). Your employer will be acting as sponsor and will help you through the application process.