Research by accountancy firm Moore Stephens found that the number of advertised positions fell to 32,900 in April 2018, down from 36,900 in November 2017.
Moore Stephens says rising costs on the high street have caused many chains to close unprofitable sites and reduce staff numbers.
It follows research by the firm which found that the number of restaurant businesses going insolvent rose 20% to 984 in the last year, up from 825 in 2015/16.
Moore Stephens says many operators have cut down on staff following the increase in the minimum wage, which rose 33p to £7.83 an hour for those aged over 25 on 1 April.
“Many restaurants simply cannot afford to remain open at the current level of staffing costs and with consumer confidence so weak there doesn’t seem to be much relief in sight,” says Simon Fowles, director at Moore Stephens.
“Five years ago, it was usual for around a quarter of revenue at most restaurants to go on wages for its staff. Now, if a restaurant spends 30% on staff pay, it is considered to be doing exceptionally well.
“Many restaurants are doing their best to avoid redundancies by freezing recruitment or reducing shift numbers by closing on quieter days, such as Mondays, but even that is a painful process.
“Struggling restaurants would really like the Government to start looking at whether payroll costs could be kept under control in areas like National Insurance.”
Rising staff costs are in addition to the increases in business rates and rents hitting many restaurants.
Last week a survey of over 600 London operators warned that spiralling costs could lead to an “exodus” of restaurants from central London, with over 80% describing their rents and rates as either “high” or “unsustainable”.