Applying for a VISA at DAR Airport (Dar es Salaam)

Hi, can anyone tell me whether it is viable to apply for a VISA at DAR Airport, as i will be flying to DAR in June for 2 DAYS. Is it very difficult to get a VISA at the airport, i will be flying in from South Africa and do not want to be delayed to long when applying, also what documentation do u need when appling.

If anyone can assist me it would be appreciated.

Regards
Craig