Some wedding guests on board a privately chartered plane that landed at Waterkloof Air Force Base had official business in South Africa, the Indian High Commission said on Tuesday.

The senior Indian officials and their delegations were in South Africa for bilateral engagements with the Free State government, according to a statement.

"The visit of Honourable Shivpal Singh Yadav, minister of public works and irrigation, and the delegation accompanying the minister, was an official visit, which took place at the invitation of the Free State government," the commission said.

"A memorandum of intent was signed between the Free State and Uttar Pradesh government for a broad based co-operation covering economic development, irrigation and agriculture sectors."

Uttar Pradesh is the most populous state of India, with around 200 million people.

Several other senior ministers and dignitaries from Uttar Pradesh were also in the plane. The aircraft, chartered by the Gupta family, carrying 270 wedding guests, landed at Waterkloof on April 30.

The guests on the flight included minister of minority welfare affairs Azam Khan, minister for rural engineering Rajendra Singh Rana, and speaker of the Uttar Pradesh Assembly Mata Prasad.

The commission said the South African Air Force gave authorisation for landing the aircraft on April 9, three weeks prior to the scheduled landing date.

"The request was made with a view to ensure appropriate security arrangements and courtesies for the visiting dignitaries in accordance with normal practice."

The mission said it submitted its initial request to use the Waterkloof "military airport" on February 28. It made subsequent communication in April to South Africa's Air Command Unit of the Air Force Command Post.

On Sunday, Justice Minister Jeff Radebe said the wealthy Gupta family used diplomatic channels when it failed to get landing rights from ministers and the Airports Company South Africa.

"The investigating team has conclusively found that in February 2013 the Gupta family approached the Airports Company SA and requested landing rights and an elaborate reception for the wedding party," Radebe said.

"This would have disrupted the functioning of OR Tambo International Airport at the time of landing, particularly the operations of the national immigration branch at the airport." The request was turned down.

In March the Guptas approached Minister of Defence and Military Veterans Nosiviwe Mapisa-Nqakula and her adviser on different occasions, Radebe said.

"On 3 April 2013 this request was also turned down."

The Guptas then resorted to diplomatic channels, with the support of an individual at the Indian High Commission.

This person "re-designated the wedding entourage as an official delegation" to enable them to use the base under the cover of diplomatic privilege, said Radebe.

Guests were attending the wedding of Vega Gupta, 23, and Indian-born Aakash Jahajgarhia at Sun City. The landing sparked widespread criticism.