Dr Nicola Theron, director of Econex, presented the findings at the Hospital Association of SA's (Hasa) annual conference currently underway at Sun City.
"Econex's preferred scenario for the envisaged cost of funding an NHIS ultimately showed a total cost of R216bn," said Theron.
"Even if the most economical model were to be applied, the figure would still equate to a total of R197bn; a number close to South Africa's entire personal income tax contributions."
She said South Africa would not be able to afford this. Theron said the NHIS endorsed universal coverage at no cost with a free choice of provider. She said the demand on the medical system would heavily outweigh the resources available.
"We found that in the face of potentially unlimited demand, we would need an additional 10 000 general practitioners and between 7 000 and 17 000 specialists relative to what we currently have," she said.
Theron said higher income households had a preference for accessing the private health sector. She said South Africa had a "pent up demand" for health services.
"If everyone is covered and there is no income constraint, the health care behaviour of the entire population would mimic that of the richest income group."
'We just can't do everything in a day'
Econex's research showed that an NHIS would result in a potential increase of four to 9.2% in respect of hospital visits, with declining public sector usage.
"Specialist visits would increase from 2.6% to 3.9% while GP visits would show a dramatic potential rise from 28.3% to 61.8%."
The research was commissioned with the intent of contributing constructively to the debate around NHIS and not to put forward exorbitant figures that suggested an NHIS was impractical, said Theron.
Dr Norman Mabasa, chairperson of the SA Medical Association (Sama) and a member of the NHI Ministerial Advisory Committee, said there needed to be a move away from an "obsessive focus on NHIS costs and timelines".
"It's the details and not timelines that should drive the pace," he said. Mabasa said practical solutions should be sought to make the NHIS work.
"Twenty three pieces of legislation would need to be amended before the implementation of an NHIS," he said.
Tony Twine, senior economist and director of Econometrix, suggested that even an additional 5% of gross domestic product added to existing government health care spend would render a NHIS very expensive.
"NHI is doable - we just can't do everything in a day. A progressive phased introduction will allow resources to be deployed economically," he said.
"Free choice of provider may not be feasible."- Sapa