A POWERFUL consumer lobby group has threatened a mass boycott of major grocery companies if they oppose the carbon tax.

Activist group Get Up has been accused of blackmail after sending a warning letter to 150 companies including Coca-Cola, Heinz, Kraft, McDonald's, Schweppes and Nestle.



Get Up says it will urge its 570,000 members to "boycott goods and services that are linked to the scare campaign''.



Get Up confirmed it was prepared to mount a national boycott of the products of any company that was "holding our climate to ransom'' by supporting a multi-million-dollar anti-tax advertising campaign by business.



Australian Food and Grocery Council chief executive Kate Carnell claimed the letter was blackmail and bullying.



"There is no doubt this is blackmail,'' she told the Herald Sun.



"I'm horrified that an entity like Get Up who supposedly encourage free speech, seems only to believe that's OK when people agree with Get Up.



"Threatening a boycott is really bullying.''

Boycotts are commonly used by activist groups in confrontations with major corporations such as PETA fighting US Gap clothing over animal cruelty issues and perhaps most famously, the Nestle Boycott, started as a grassroots movement against the Swiss giant after it was found selling dangerous baby formula to third world countries

Ms Carnell said some of her smaller members who received the letter were worried the boycott could cost jobs.



"They are saying to our members if you support the Australian Food and Grocery Council taking a position against the carbon tax then we will encourage our members to boycott your goods and services,'' she said.



Other companies who received the letter include Arnott's, Colgate-Palmolive, Foster's, Johnson & Johnson, Mars, Sanitarium, Unilever, Patties Foods, Jalna and Eagle Boys Pizza.



Ms Carnell said her members were not climate change deniers but they did have concern about the carbon tax harming competitiveness and the 300,000 jobs in the food and grocery sector.



Get Up national director Simon Sheikh, who has led campaigns to ban live animal exports, improve financing for mental health and support for gay marriage, wrote to the companies this week.



"It is our intention in the next few days to provide easy to use product information to our membership such that they can boycott goods and services that are linked to the scare campaign that the Australian Food and Grocery Council are about to sign up to,'' the letter said.



He wrote that the public "may see your company as being supportive of the scare campaign'' and he was writing to give them the chance to denounce it and resign from the Food and Grocery Council.



Mr Sheikh said Get Up had used its power to pressure banks to stop supporting environmentally destructive investments and believed individual food companies did not share the view of their lobby group.



"We're not just going to roll over and allow industry to hold our climate to ransom, which is why we're clarifying individual companies' positions and seeking to hold them accountable,'' he said.



"We've asked company CEOs to answer a series of questions, including whether they accept the science of climate change, whether they back a carbon price, and whether they would consider resigning from the industry body, and we intend to make that information public.



"Australians will then be able to take that information into account when they enter the supermarket.''

For more on Get Up's threat of a boycott of major grocery companies if they oppose the carbon tax go to the Herald Sun.