A 7-Eleven pay deal for workers has been rejected because it would have underpaid workers by about $80 a week.

The Fair Work Commission has rejected an enterprise agreement proposed by a 7-Eleven franchise in Sydney because it failed the commission's test to ensure workers are better off overall, compared with award wage rates.

Commissioner Julius Roe gave the franchise, trading as 7-Eleven Rozelle and 7-Eleven Bexley, an opportunity to ensure that proposed weekend rates would provide adequate compensation for any loss of award entitlements.

Given that 7-Eleven stores operate 24-hours a day, Commissioner Roe said the potential for employees to work a large proportion of hours at night and the weekend was "not fanciful".