Johannesburg - Officials at London's Heathrow airport have announced a restriction on all airlines at the airport until 6am on Thursday, which means SA Airways will make only one trip out of the three it announced earlier on Tuesday.
"Air traffic control in London Heathrow have informed us that we can only land one aircraft out of South Africa," said SAA spokesperson Fani Zulu as airlines globally deal with the backlogs caused by bad weather.
"We apologise to our passengers for this latest development. We would have loved to fly three flights out of South Africa to London Heathrow. We are, however, dependent on what the air traffic controllers in London are telling us."
Flight SA234 would leave OR Tambo International in Johannesburg on Tuesday.
Zulu urged passengers to confirm their booking before setting off to the airport.
SA220 out of Cape Town to London has also been cancelled.
One flight will come out of London - SA235.
Zulu said in addition to the congestion at Heathrow, authorities were battling with ice on the runway.
The extreme cold had led to burst water pipes on one of SAA's planes waiting in London on Monday night.
Zulu said passengers who want to postpone their flights should contact the SAA call centre, as this would free up seating for passengers who were stranded in the country.
SAA would provide a full refund to passengers who want to cancel completely.
"We also request any SAA passengers who are able to postpone to consider that. On our side, we will certainly give a full refund to cancel or will assist with booking at a later date."
British aviation authority BAA said in a statement on its website: "Given ongoing weather problems affecting airports across Europe, the situation is under constant review. Further snow is forecast across Europe today and there may be further delays and cancellations. Please contact your airline for confirmation before leaving for the airport.
"We are truly sorry for the disruption the weather is causing to our passengers. We are doing everything we can to get you on your journey," it concluded, as travellers stranded in Heathrow started complaining of "Third World" conditions at the airport.
In an interview with BBC radio, BAA chief executive Colin Matthews apologised for the situation. He said they would have to look at investing in more ice and snow clearing equipment as they had planned for a normal winter - not the extremes recently experienced.