The chief constable of North Wales Police says officers could be taken off the beat because of the latest budget settlement from the UK Government.
The Home Office said the increase in police grant was above inflation
Richard Brunstrom said that in real terms there has been a cut in his force's budget of £3m.
Meanwhile, South Wales Police said they were "disappointed" at the budget set for 2007-8. Dyfed-Powys said the future was "distinctly bleak".
The Home Office said the increase in grant was above inflation.
But Mr Brunstrom claimed the rate of inflation within the police force was 5.1% in north Wales.
He added: "Not only are we losing backroom staff, we are having to take officers off the beat in order to fill in the gaps."
North Wales Police made £2m cutbacks last year, with further cuts of about £3m expected this year.
Mr Brunstrom said the settlement could mean fewer officers
The force announced in October that 120 civilian posts would be lost, with police officers having to fill some of those jobs.
South Wales Police Deputy Chief Constable David Francis said the level of police grant was much lower than was needed and would "undoubtedly lead to some difficulties".
He added: "That said, we are currently looking at all our options and opportunities to improve efficiency and savings prior to our budget being set next month.
"Although this process is currently ongoing, I do not envisage having to shed any of our existing workforce through enforced redundancies."
Dyfed-Powys Police confirmed they were facing a funding shortfall for the 2007-8 financial year, but hoped to manage this using reserves and making "additional efficiencies".
But the force said it could not rule out job cuts if the police grant was reduced further in subsequent years.
A spokesperson said: "The home secretary has hinted that funding increases for the police service may be no more than 1.9 %.
"We cannot at this stage rule out the need for service reductions and/or job cuts in 2008-9."
Gwent Police said they were planning efficiencies now to minimise any future shortfall in budgets.
A Home Office spokesman said government and central spending on the police had increased by 56% - almost £4bn - between 2000/01 and 2007/08.
He said: "The 2007/08 funding settlement provided an increase of a minimum 3.6% for every police authority in England & Wales.
"This increase of 3.6% is above inflation (around 2.7%) and is higher than last year's settlement."