Three-quarters of companies provide more than the statutory maternity pay requirement, according to research by Incomes Data Services (IDS).
The survey also revealed that about half (52%) of respondents think that the current statutory minimum maternity pay for women is too low.
IDS surveyed 115 organisations, which collectively employ 470,415 people.
Since April 2007, all pregnant employees are entitled to 52 weeks' maternity leave regardless of the length of service with their company. Statutory paid maternity leave is 39 weeks, with only the first six weeks paid at 90% of the employee's average weekly earnings, and the remaining 33 weeks at a 'prescribed rate' of £117.18 per week.
The findings appear against a backdrop of recent reports suggesting that the government was considering delaying the extension of the maternity pay period from 39 to 52 weeks.
TUC general secretary Brendan Barber said: "The government should not use the recession as a reason to delay planned improvements to maternity pay and family-friendly working. Increasing maternity pay would not be a huge extra cost to business and would help companies recruit and retain highly skilled female employees."