Cabinet has endorsed the preliminary findings of an investigation into the landing of a private plane linked to the Gupta family at Waterkloof Air Force Base, and said those involved must face sanction.

However, no details of the report, handed to Cabinet on Wednesday, have been released yet.

"Those who are found to infringe and compromise regulations must face the full might of the law," acting government spokeswoman Phumla Williams told journalists on Thursday, following the executive's regular fortnightly meeting.

She reiterated government's position that the landing was unauthorised.

Ministers in the justice, crime prevention, and security cluster would hold a news briefing soon to announce the outcome of the probe.

In the meanwhile, Public Protector Thuli Madonsela has responded to a request by the Democratic Alliance to investigate the matter by saying that, on the face of it, it appeared to fall within her mandate.

However, Madonsela said she would ask for access to the preliminary report before deciding whether to proceed.

"This information will place me in a better position to conclude the assessment process and to exercise my discretion whether to investigate and which issues to pursue," she said in a letter to DA MP David Maynier.

The government investigation was announced on May 3, a few days after a private plane chartered by the Gupta family landed at Waterkloof, a national key point.

The aircraft was carrying 270 guests to the wedding of Vega Gupta, 23, and Indian-born Aakash Jahajgarhia at Sun City.

Government faced a storm of criticism over the incident, given the perception that the Gupta brothers are close to President Jacob Zuma.

Five high-ranking officials and military personnel have been suspended over the unauthorised landing.

Eight Tshwane metro police officers were also suspended for allegedly escorting and providing unofficial security to Gupta wedding guests, from Waterkloof to Sun City.