A preliminary report will be released by the Gauteng health department on Sunday after a "speedy investigation" into why Martha Marais, 76, was restrained under a bench and made to lie on a floor at Mamelodi Hospital earlier this week.

Health MEC Dr Bandile Masuku will release the findings after going to see the family.

"I am satisfied with progress made and the matter will be resolved speedily in line with the values of human dignity and the protocols that govern health professionalism,” Masuku said.

"We reiterate that the dignity of patients must be upheld at all times and our facilities must be havens of healing, safety and comfort."

Marais's family has laid assault charges against the hospital after her daughter, Stephnie on Wednesday found her hungry and dehydrated mother lying under the bench, with her hands tied to it.

By Friday, the family had still not been told why she had been restrained.

Family spokesperson Viginia Keppler had said Marais was not a violent person and in the event that she had had a psychotic episode, she was so old and fragile that she could do no harm.

Department spokesperson Lesemang Matuka said it also welcomed the Human Rights Commission investigation into the "Marais incident".

"As a Chapter 9 institution, the SAHRC is empowered by the Constitution of the Republic to deal with human rights abuses whenever they occur. Gauteng Health will support the investigation."