JOHANNESBURG (Reuters) - South African private sector activity grew in May as new order volumes stabilised and business confidence improved, a survey showed on Wednesday.

The S&P Global South Africa Purchasing Managers' Index (PMI) rose slightly to 50.4 in May from 50.3 in April. A reading above 50 denotes growth.

"Firms appeared to prioritise building stocks in anticipation that sales would start to recover, particularly as other economic drivers such as supply chain conditions and load shedding (power cuts) are also stabilising," said David Owen, senior economist at S&P Global Market Intelligence.

Many companies are confident that demand will start to pick up following the May 29 election, Owen added.

The African National Congress - once led by Nelson Mandela - lost its majority for the first time in last week's election with markets closely watching who it will partner with to govern the nation.

(Reporting by Bhargav Acharya; Editing by Christina Fincher)