French oil major Total has decided to postpone its application for additional drilling in a South African offshore gas block, a letter seen by Reuters from the consultancy conducting the environmental and social assessment showed.

The delay is a potential blow to South Africa as it seeks to reduce its reliance on coal and increase the use of natural gas and renewables in its energy mix.

More than 80% of the power supplied in South Africa comes from coal-fired plants, making it one of the world's biggest CO2 emitters.

The government has suggested that gas from Total's fields could eventually be used as feedstock at South Africa's ailing 45,000 barrel per day gas-to-liquid refinery at Mossel Bay, which has run out of domestic gas feedstock.

Total discovered two large gas fields, Brulpadda and Luiperd, in offshore block 11B/12B in 2019 and 2020, about 175 km off the southern coast.

"This letter serves to notify you that TOTAL E & P South Africa B.V. has decided to postpone their application for the additional drilling and associated activities in Block 11B/12B at this time," said the letter from the SLR environmental consultancy to stakeholders, dated April 13.

An official at SLR Consulting confirmed the authenticity of the letter but did not disclose reasons for the delay.

"Thus, the application for Environmental Authorisation of the additional drilling and associated activities in Block 11B/12B has been withdrawn," SLR Consulting said.

Total did not immediately respond to a request for comment.