The move, which is likely to see it target the few remaining independent societies as well as smaller independent chains, would take the movement's combined grocery market share to just under 10%.
Chief executive Peter Marks said the society had no intention of resting on its laurels after the Somerfield buy and would be "watching for more acquisition opportunities".
The Co-operative Group is converting former Somerfield stores at a rate of 24 a week, with the complex programme expected to reach completion by the first quarter of 2011.
However, recent interim figures showed sales through converted stores to be disappointing. Customers had not reacted well to the upheaval, Marks said, but he was confident trade would return "once the dust settled".
"The important thing is that the business as a whole isn't suffering and that profits are continuing to go up. Profits will be above £400m this year," he said.