Companies said they expect a quarter of their staff to work beyond retirement age in the next 10 years; it means 6.3% of the working population will be over the age of retirement. Currently, the proportion is 2.6% - about 752,700.
Martyn Bogira, Prudential's director of defined-contribution solutions, said: "Staff face the stark choice of either having to save more for their pension from an earlier age or having to work longer if they are to avoid taking a significant drop in their standard of living in retirement."
The research also revealed a strong north/south divide. Companies in the north expect 16.2% of staff to work past the statutory retirement age. This compares with just 2.4% of staff in greater London and the South East.
The statutory retirement age for men and women is due to rise to 68 by 2046.