Only 18 of the 43 comms directors at the companies interviewed for Eloqui PR by the Leeds Business School Centre for PR Studies said their budgets had increased over the period.
Thirteen said their PR budget had stayed the same while 12 said they had seen their funds for communications cut over the last two years.
The survey found that 40 per cent of those interviewed expected to see an increase in their budget over the next year.
The report, produced by a team led by IPR president Professor Anne Gregory, also investigated the amount of money PR departments had to spend in a given year.
Just over half (52 per cent) said they invested more than £1m a year in PR while 36 per cent spent under £500,000.
‘What is clear from the results is that good communications need not rely on extensive human resources,’ the report said.
‘A small staff can still achieve good results.’