South African National Airways (SAA) took the decision to cancel all its flights for Saturday between South Africa and Zimbabwe.
The flights affected from Johannesburg to Harare are SA 022, SA 028 and SA 024. The flights affected from Harare to Johannesburg are SA 025, SA 023 and SA 029.
Customers were told on the SAA Facebook page to contact their nearest office for rebooking.
It said it would keep people updated on the status of Sunday's flights on that route.
SAA earlier confirmed to Traveller24 that the decision to impose the restriction emanates from the requirement from Zimbabwean authorities of a Foreign Operators Permit, from the airline to continue to operate in that country. SAA operates a total of nine flights daily to three destinations in Zimbabwe.
"Every effort will be made to assist all affected passengers and our recovery plans have been activated. SAA is monitoring the situation and will provide updates on a regular basis and when there are developments," said SAA spokesperson Tlali Tlali.
Earlier on Saturday, Transport Minister Joe Maswanganyi said he would be meeting all aviation entities from the department to discuss the grounding of the Air Zimbabwe aircraft on Friday, allegedly due to non-compliance.
The department said the Air Zimbabwe flights' main issue was the required Foreign Operators Permit, together with other documents, which must be on-board an aircraft at all times, and made available for inspection on request by the relevant authorities.
"As a result, the South African Civil Aviation Authority (SACAA) has instructed the operator not to take off until such time that there is full compliance with the applicable South African civil aviation regulations and the requisite international aviation standards as set by the International Civil Aviation Organization."
Maswanganyi apologised for inconveniences that might have been caused to passengers, the department said.
"In the same vein, the Minister emphasised that civil aviation safety and security is critical, and all licence and permit holders operating into and within the South African airspace need to comply with the applicable international standards, and the South African civil aviation regulations."
The Friday flight was set to take off for Harare shortly after 18:00 but was cancelled before then.
'It seems that tensions are mounting'
Zimbabwean President Robert Mugabe and his wife Grace are in South Africa for a Southern African Development Community (SADC) meeting underway in Pretoria.
Mugabe's personal airplane, operated by Air Zimbabwe, is not believed to be affected by the cancellation.
DA Shadow Deputy Minister of Finance Alf Lees however, disagreed saying the grounding of flights, between SAA and Air Zimbabwe, seemed to be due to the diplomatic impasse over the assault charges against Zimbabwean First Lady, Grace Mugabe.
"Now, it seems that tensions between Zimbabwe and South Africa are mounting, leading to airlines being grounded."
He called on Finance Minister Malusi Gigaba to urgently address "these concerning incidents".
"The silence from our government on the Grace Mugabe matter has been deafening. The reality is that the South African government has completely mishandled this situation, which is now affecting the operations of the national airline."
Meanwhile, a "red-alert" was issued by police in the event that Grace attempted to cross the SA border after she allegedly assaulted a 20-year-old model in a Sandton Hotel on Sunday.
Air Zimbabwe is operated by Mugabe's son-in-law, Simba Chikore.
In 2011, an Air Zimbabwe Boeing 767-200 was seized in London over a $1.2m debt. Later that year, a Boeing 737-500 was impounded by South African authorities after the airline failed to pay a $500 000 debt, the African Independent reported.
In April, all five Air Zimbabwe planes operating in South Africa were grounded when it was declared not airworthy.
In May, the airline was banned from flying to Europe over safety concerns. -- News24