He said it was not possible to do anything meaningful about the so-called "second economy", without the full cooperation and sacrifice of the first.
To laughter and applause he said a shift in mindset was required for the middle class to relinquish its "greediness, arrogance, short-termism and stupidity".
Both economies needed to be transformed into a development state in order to alleviate the unequal power relationship between them.
"The vested interest of the South African middle class in the glory of their own status is too strong," he said.
The rich and the poor were drifting in opposite directions, creating a tension which would result in popular uprising.
"The question is when it will happen and what will be its intensity."
Terreblanche said South Africa's history showed that the arrogance and short-sightedness of first the English and then the Afrikaner middle class had led to their downfall.
The black middle class would meet the same fate at the hands of poor blacks, he said.