"It is unfortunate to come to the realisation that I have never in any meaningful way been the head of policy; I was given all of the responsibility and none of the basic levers to do the job," she added.
Ngwenya said that the party's policy unit was staffed with researchers who could not meet the party's requirements.
"On my arrival I conducted a skills audit of the researchers in the policy unit. It was soon apparent that, for all of them, this was their first serious research job and that they had recently graduated from university. We were trying to extract from those researchers more than they could reasonably deliver.
"The policy offer for the national government in waiting should not rest on the shoulders of three inexperienced researchers."
She claimed that many senior leaders had expressed to her that the researchers were not up to the task, but she could not immediately dismiss them without placing the DA in violation of labour laws. She said the lack of budget affected policy development.
"There was the possibility to motivate for funds on a case by case basis, but it was made clear that only a small amount was available that could cover refreshments for workshops and so on."
She said this had resulted in there being no budget to meet with experts around the country, party constituents, to purchase data, reports, software and other things necessary to run a competitive research operation.
"There is no reason why the party cannot have a policy unit that rivals any of the think tanks from which we constantly seek advice. However, setting up such a unit will require a reasonable financial commitment from the party," she said.
"The party spends more on temporary billboards and other marketing than it does on developing a longer-lasting comprehensive policy blueprint for the country."
She said that the DA had failed to sign off on drafted terms of reference to situate the policy unit within the party, and to outline how it interacted with other structures.
Party spokesperson Solly Malatsi thanked Ngwenya for the work she had done on developing the party's policy platform, which he said would culminate in the launch of an election manifesto. Malatsi said Ngwenya would move to the energy portfolio committee in the National Assembly.