TRADE union Solidarity launched an all-out campaign to boycott Woolworths after the retail giant ignored a midday deadline to remove advertisements the organisation claims is racist towards white job seekers.

Minutes after the deadline passed Solidarity kicked off its "Woolworse - Making a Differentiation" campaign in a cleverly-worded sleight on the retailer's slogan "Making a Difference".

The union's reaction came in the wake of a furore over the adverts - one of which called for "African black" candidates only - on social networks.

Outspoken celebrities like Steve Hofmeyr joined the chorus of protests with Twitter postings like: "Gonna be hard, but goodbye Woolies."

Three adverts for vacancies in the Western Cape, published on the Woolworths website, state that in accordance with employment equity, the positions were for coloured, black or Indian applicants.

Woolworths has denied that the adverts are racist.

"Like all South African companies, Woolworths has a role to play in transformation. For this reason some positions [where there is under-representation] are designated groups," the company said in a statement. "The designated groups are Africans, coloureds, Indians, women and people with disability. It is not true that all positions are reserved for these designated groups."

But Solidarity deputy general secretary Dirk Hermann said employment equity did not make provision for "absolute exclusions", as was the case with the advert that called for "African blacks" only.

"These adverts were for positions in the Western Cape where there are a lot of coloured people living. To specify a 'African black' for a specific job therefore counteracts equal employment practices because it implies that these coloured people might be excluded from getting the job."

Hermann said the campaign would be driven on social media platforms, and a website established. "It's all systems go [for this campaign]."

The campaign is supported by the Pro-Afrikaans Action Group, whose leader Dr Dan Roodt, said "this latest manifestation of anti-white racism is the final straw" in the organisation's grievances with Woolworths.