The panel was convened at the request of the Treasury.
In a draft working paper, they say the accelerated and shared growth initiative of South Africa (Asgisa) focuses on "capital deepening", a big increase in economic infrastructure, which the government expects to generate economic growth and create jobs.
But international and local experience suggest that capital is not "where the key to growth accelerations lies", says the paper.
"Capital at most explains about a third of growth accelerations."
Compounding the problem is the fact that South Africa needs more investment to generate growth than other countries.
The paper also asks how the "sizeable increase in public investment" anticipated by Asgisa will be funded.
Should the money come from domestic sources, interest rates would rise. If it was drawn from abroad, further pressure would be put on the balance of payments.
full story from M&G here