The supermarket, which currently operates 121 pharmacies across its 735 stores, plans to increase the number of stores that offer the service as it seeks to catch up with Tesco's 199 locations.
The initiative, which could add 50 pharmacies to its portfolio, is intended to give customers more reason to go to Sainsbury's as it grows its non-food offer.
Deregulation of the pharmacy sector, which could happen as soon as April, will mean licensing restrictions are loosened, enabling fast-track licences to be granted to stores that stay open for more than 100 hours a week.