Namibia has discontinued the use of Russia's Sputnik V Covid-19 vaccine following concerns raised by neighbouring South Africa, the health ministry said on Saturday.

Neighbouring South Africa earlier this week said it would not approve Sputnik V due to concerns it could increase the risk of HIV infection among men.

The Namibian health ministry said in a statement that following South Africa's decision it was suspending, with immediate effect, use of the shots until the formula is listed for emergency use by the World Health Organization.

"The reason for discontinuation of the administration of the vaccine is being done out of abundance of caution that men who received Sputnik V may be at higher risk of contracting HIV when exposed to it," said the ministry.

Namibia had taken delivery of a Serbian donation of 30,000 Sputnik doses -- out of which less than 120 have been administered so far.

South Africa's health products regulator on Monday said it would not authorise use of Sputnik based on earlier studies testing the safety of a modified form of adenovirus -- a type of virus that causes respiratory infections -- known as the Ad5 and contained in the Russian jab.

But Russia's Gamaleya Centre, which developed Sputnik V, said it would produce information to show that South Africa's concerns were "completely unfounded".