He said the PA had yet to commit to forming a government that was not based on a short-term scramble for positions.
The PA had pushed for a motion of no confidence, backed by the ANC, in Nelson Mandela Bay Mayor Retief Odendaal.
Steenhuisen said the DA could not reconcile working with the PA in Johannesburg while the party was determined to remove a DA mayor in the Eastern Cape metro.
"The existing ongoing arrangements the PA has with the ANC confirm that the PA is not willing to position themselves unequivocally outside the ambit of the ANC," he said.