Cardiff-based retailer Bhoo Patel has collected 5,000 signatures for a petition against proposed Tesco Express developments in the Welsh capital.
Bhoo, who owns Philog Stores in the Whitchurch area, has formed an action group along with other traders in a bid to block Tesco. He presented the petition to Cardiff council in the hope it will reject Tesco's plans to extend a former wine shop on Birchgrove Road.
Bhoo said that although Tesco had already begun work on the site, he was determined to keep fighting. He argued: "This is still not a done deal. People power can still have a big impact here."
The campaign has received the backing of local MP Julie Morgan, who was among 120 at a public meeting against the development. Morgan wrote to Tesco urging it to rethink its plans, citing community concerns about the threat to local shops and the impact on traffic.
Morgan held a meeting with a Tesco official in Westminster last week and Tesco has now agreed to meet interested parties on July 7. Meanwhile, the council is due to discuss Tesco's planning application on July 18. It hopes to open the store some time in August.