Jamie Oliver's restaurant group has signed up to sell an ethical brand of cola.

His Jamie's Italian and Barbecoa restaurants will offer Karma Cola from next week, but Oliver has stopped short of replacing Coca-Cola, which will still be offered at the eateries, the Daily Mail reported.

Karma Cola, founded in New Zealand in 2012, is promoting its Karma Cola Sugar Free, launched this month, with the words "drink no evil".

The celebrity chef made headlines earlier last year when he said he would campaign to stop Coca-Cola being a sponsor of the Olympics.

Karma Cola was founded in New Zealand in 2012. Photo / Supplied
Karma Cola was founded in New Zealand in 2012. Photo / Supplied

The father-of-five has long favoured a sugar tax on fizzy drinks.

Simon Blagden, chief executive of Jamie's Italian, said the chain makes food with "responsibly sourced ingredients' and it is great to offer "the same choice when it comes to that occasional soft drink".

Karma Cola is also launching a new Chili Karma Cola exclusively with Wahaca.
Its original recipe is made with Fairtrade Organic cane sugar and kola nut grown in Sierra Leone.

Karma Cola's co-founder Simon Coley said the UK has become its second largest market.

It is sold through Waitrose, Ocado, Ceviche, Restaurant Story and by many independent restaurants and cafes.

The company is also behind Karma Cola Gingerella Ginger Ale, stocked by the Byron hamburger chain, and Karma Cola Lemmy Lemon.