The force's assistant Chief Constable Paul Netherton admitted to be "concerned" at the multiple demands being placed on the force in June.
Up to 100 officers from Devon and Cornwall are to be abstracted for three days' training and a week-long deployment to Northern Ireland in mid-June as world leaders gather in County Fermanagh.
At the same time, the force is providing "mutual aid" to Avon and Somerset to police potential flashpoints during the badger cull, which is scheduled to start on June 1.
"Both are happening at the beginning of the summer and of peak demand on our services when we see a big rise in the number of people coming into places like Newquay and Torquay," Mr Netherton said.
"We are being very careful to make sure we are not dipping to below our required safety levels, although the G8 summit is only for a week."
Mr Netherton said while not short of volunteers for the Northern Ireland deployment, officers were being chosen from different departments and locations to lessen the impact.
Restrictions have also been put on certain officers taking leave, as the force tries to back-fill the temporary vacancies.
"I am concerned at our ability to respond to multiple events that are taking place at the same stage," Mr Netherton added. "It would make some sense to stagger them in some way."
A variety of officers from the region, including firearms and personal protection specialists as well as public order units, are expected to join up to 4,000 officers from England, Wales and Scotland in Northern Ireland.
The summit will see US president Barack Obama, Russian president Vladimir Putin, German chancellor Angela Merkel and others gather for two days at Lough Erne golf resort in Co Fermanagh.
It will be the first time the annual summit has been held in the UK since Gleneagles in Scotland in 2005.
The Police Federation in Devon and Cornwall, which represents constables, sergeants and inspectors, blamed the Government for a lack of "joined-up thinking".
Branch chairman Sergeant Nigel Rabbitts said the looming problem had been made worse by the recent loss of 400 officers because of Government budget cutbacks, which had undermined the force's "resilience".
"Officers will either have to work overtime or be taken from other duties to cover," he said.
"It doesn't seem like joined-up thinking from the Government, especially given the impact on police resources because of restructuring of budgets.
"We have always said reducing officer numbers would affect the resilience of the force, particularly when there are additional operational demands."
Two culls of disease-carrying badgers, on Exmoor and in Gloucestershire, are to be carried out this year as part of a package of control measures for bovine TB.
Up to 5,000 badgers could be killed in the two areas during the four-year cull period. If found to be effective in combating the disease, which has ravaged cattle herds across the region, the "pilot" culls could be rolled out.
Devon and Cornwall Police have been closely involved in planning the policing response with neighbouring Avon and Somerset.
Contingency plans have been put in place if the local offices of the Department for Environment, Food and Rural Affairs or the National Farmers' Union are targeted by protesters.
Avon and Somerset Police has said it will "engage with protesters to facilitate safe, peaceful and lawful protests" but stressed its role was "to uphold the law by responding to any reports of criminality or public disorder".
