document: North Wales Chief Constable Mark Polin said the police were likely to "bear the brunt" of further cuts to the Home Office budget by 2020.
  Dyfed-Powys Commissioner Christopher Salmon has urged ministers to take rural needs into account when changing the police funding formula.
  The Home Office has said no decisions have been taken beyond this year.
  Mr Polin sent an email to North Wales force employees responding to a UK government statement that by 2020 the Home Office would have only half of the funds it had in 2010.
  He said: "The police service represents the largest slice of the Home Office budget and therefore it is a realistic assumption that we will bear the brunt of any such reduction.
  "Indeed, a further cut of between 25% and 40% is being suggested and you won't need me to tell you how this would represent a significant challenge for us (and other forces) to achieve in addition to that we have already saved and plan to save."
  North Wales Police and Crime Commissioner Winston Roddick said the force had achieved "tremendous success during a time of great challenge".
  "Further cuts are inevitable and will put greater pressure on staff and resources," he added.
  Meanwhile his Dyfed-Powys counterpart Christopher Salmon - supported by three of the region's Conservative MPs - called for "fair funding" for rural areas in the current consultation over changes to the Police Allocation Formula, which the Home Office says needs updating.
  In a letter to ministers, Mr Salmon and the MPs - Chris Davies, Glyn Davies and Simon Hart - claimed the new formula would favour heavily-populated urban centres and make little allowance for the extra costs associated with policing rural areas.
  "We urge, on behalf of the people of Dyfed-Powys, that the government recognises the limitations of urban-based statistics in describing rural areas," the letter said.
  "We also urge that the government does not neglect the additional cost of providing services to those areas, from additional fuel costs to the additional infrastructure required to maintain a reasonable emergency response."
summary: Senior figures at two Welsh police forces have raised fears about their funding in the coming years.