Speaking at the association's annual summit, held in Birmingham this week alongside the National Convenience Show, he claimed the multiples were not living up to their public pledges to create thousands of new jobs.
Using data gleaned from the 2010 annual reports of Tesco and Sainsbury's, he said that although the retailers had created 2.75 million extra square feet of selling space between them during the year, they recruited 426 fewer staff than in the previous year. "Supermarkets are saying: 'We're the good guys here. We can create loads of jobs but to help us do that we need you to liberalise out-of-town planning laws,'" he said. "You'd think the extra selling space would lead to a significant increase in jobs, but it hasn't."
He added: "I'm not tackling Tesco and Sainsbury's. But building big out-of-town stores does not lead to an increase in jobs. Our campaign must be about stopping the government listening to supermarket propaganda on out-of-town developments and seeing that growth can come from sustainable town centres."
Lowman added that the supermarkets were "licking their lips" at the prospect of weaker guidance as part of the Localism Bill, which would allow them to "outgun" councils to get planning applications through.
He also claimed that 2011 could turn out to be the biggest year for the convenience sector since 2006. That year, the sector had to battle a possible relaxation of Sunday trading laws. In 2011, c-stores face the threat of a tobacco display ban as well as the Localism Bill.
"We are making our voices heard to ministers as they prepare their budget and growth strategy and we are preparing to win hearts and minds in every council house and town hall in the country if we have to," Lowman said.
"This is a fight that we must win."