Glass Lewis said adoption of the proposal from responsible investment group ShareAction "could border on micromanagement by shareholders."

"We believe that with a matter as dynamic and company-specific as the wages paid to employees and contractors, it may not be appropriate to allow shareholders or a third party to dictate those terms," it said.

It also warned the resolution's adoption could "hem the company into a constrained position" if market conditions changed.

ShareAction had co-ordinated the filing of the resolution by an investor coalition that includes Legal & General and Nest.

Sainsbury's annual general meeting is on July 7.

The real living wage was established by the Living Wage Foundation charity and independently calculated by the Resolution Foundation think tank, according to how much workers and their families need to live.

The rates are currently 11.05 pounds ($13.56) per hour in London and 9.90 pounds per hour in the rest of the United Kingdom. That compares with Britain's main government-mandated minimum wage rate of 9.50 pounds per hour.

The Bank of England is watching pay closely as it weighs up the risk that the recent jump in inflation to a 40-year high of 9.1% becomes embedded in the economy.

Sainsbury's has since May been paying real living wage rates to all its directly employed staff but is not doing so for all its third-party contractors, such as cleaners and security guards.

"To effectively balance the needs of our customers, colleagues, suppliers and shareholders we must preserve the right to make independent business decisions which are not determined by a separate body," a spokesperson for Sainsbury's said.

Sainsbury's is recommending shareholders vote against the resolution. The company has a workforce of 189,000, making it one of Britain's biggest private-sector employers.

($1 = 0.8146 pound)

(Reporting by James Davey in London; Editing by Matthew Lewis)