Harry Schwarz, who spent his career in South African opposition politics, died on Friday at the age of 85.

"Harry Schwarz will be remembered for his signal contribution to the development of our democracy," Democratic Alliance leader Helen Zille said.

"He had strong leadership qualities and could inspire people to great achievements," she said.

Schwarz began his career in the United Party (UP) in 1951 when he was elected to the Johannesburg city council.

He and other liberal reformers, called the "Young Turks" took control of the party in the then Transvaal in 1974. Among those reformers was David Dalling.

Dalling was a fellow traveller in opposition politics and later became an African National Congress parliamentary whip.

"I and myself and others who were called the Young Turks walked through deep waters with him," said Dalling. "As a result of his leadership we helped to reshape the political landscape at the time, trying to move it to a more open, progressive landscape." Following their takeover of the Transvaal UP, in an election the same year Schwarz was sent to parliament as an UP MP. This experience was short-lived as he found himself expelled from the party the following year after he signed the Mahlabatini Declaration with Inkatha Freedom Party leader Mangosuthu Buthelezi.

Schwarz also became one of the founders of the Democratic Party (DP), the forerunner to today's DA.

"The DP made a fatal mistake by merging with the Nats. It should have sought an alliance with black political groups. There's room for a black party in which whites play a part [but] at the moment the DA will go nowhere," Schwarz said in a 2008 interview with the Financial Mail.