Twitter user Dion, amidst a two hour delay to his flight, tweeted it was due to a strike at South Africa's busiest airport.

The airport replied, stating there was no strike and directed him to a statement on its Facebook page.

The release stated that Air Traffic and Navigation Services (ATNS), responsible for the running of South Africa's air traffic control systems, experienced a technical malfunction.

The malfunction interrupted communication between the air traffic controllers at the Johannesburg air traffic control centre, based at OR Tambo International airport, and the air crews on flights operating at the airport and in the airspace vicinity on Monday.

"This situation was recovered within 25 minutes and all operations returned to normal. During a review of the communications failure on Wednesday, 7 October 2015 it became evident that further risk mitigations required to be implemented," the statement read.

"In order to maintain the normal high safety standards expected in the aviation industry and from ATNS, air traffic rates to and from the airport and in the airspace have been limited temporarily while technical risks are mitigated."

The "unfortunate result" of what the airport described as a necessary safety intervention were the flight delays.

"ATNS is currently busy with all the required activities to normalize the situation and restore the capacity for the airport and airspace. ATNS is not aware of any industrial action," the airport said.

"The regulation and control of air traffic is classified as an essential and as a result the service delivery of ATNS continues."

-News24.com