England all-rounder Ben Stokes has been fined 15 per cent of his match fee for the fourth Test against South Africa after his altercation with a fan at the Wanderers.

Stokes issued a statement on Friday apologising for his choice of language in an exchange with a spectator.

The all-rounder was dismissed for two on the opening day in Johannesburg and was heard on a live broadcast aiming expletives at a member of the crowd.

After Friday's play, Stokes – who claimed to have been "subjected to repeated abuse" – took to Twitter to say sorry for his "unprofessional" reaction.

And having assessed the incident, the ICC took action on Saturday.

"Ben Stokes has been fined 15 per cent of his match fee for breaching Level 1 of the ICC Code of Conduct during the opening day of the fourth Test against South Africa at the Wanderers," read the ICC's statement.

"Stokes was found to have breached Article 2.3 of the ICC Code of Conduct for Players and Player Support Personnel, which relates to "use of an audible obscenity during an International Match".

"In addition to this, one demerit point has been added to the disciplinary record of Stokes, for whom it was the first offence during a 24-month period.

"Level 1 breaches carry a minimum penalty of an official reprimand, a maximum penalty of 50 per cent of a player's match fee, and one or two demerit points."

The ICC said the fact Stokes had admitted the offence and accepted the proposed sanction from ICC Elite Panel of Match Referees Andy Pycroft meant a formal hearing was not required.

England, leading the four-match series 2-1, are in a strong position after scoring 400 in their first innings, with Pieter Malan, Rassie van der Dussen and Dean Elgar falling early in South Africa's reply on day two.