The official British Monarchy website called for applications for a part-time cleaner at Windsor Castle, offering the successful maid STG6.67 ($NZ13) per hour, British tabloid the Daily Mirror reported.
The hourly rate is STG0.47 above Britain's minimum wage but STG0.78 below the government's recommended "living wage".
It means the cleaner - who would perform tasks including vacuuming, mopping, dusting, and changing bed linen - working from 8am to 1pm Monday to Saturday, would earn a full-time equivalent salary of STG13,000 ($NZ25,200) a year.
"This looks really bad. Since the Queen receives considerable support from the public purse she should pay a living wage, not just barely a minimum wage," Labour MP Grahame Morris told the newspaper.
"She's setting a bad example to other employers."
In June Windsor Castle advertised for a servant to work 40 hours a week for STG14,000 a year.
A royal spokesman told the Daily Mirror: "We are reviewing our policies regarding the living wage".