Greater Manchester Police will lose a quarter of its staff, including front-line officers, as it faces a £134m budget cut in the next four years.
Greater Manchester Police Authority (GMPA) said nearly 3,000 posts would have to be cut from its 12,000 staff.
A total of 1,387 officers and 1,557 civilian posts could go. A recruitment freeze is also planned for 2011-12.
The prime minister's spokesman said the government wanted as many resources as possible "devoted to the front line".
The proposals will be presented in a joint report from Chief Constable Peter Fahy and the authority's treasurer at an authority meeting on 22 November.
"Protecting frontline policing is at the heart of the plans we have been developing," Mr Fahy said.
"As the majority of our money is spent on staff it is inevitable that there will be an impact on our people."
The authority plans to cut 2,944 jobs over four years, with staff being offered voluntary redundancy.
It also plans to reduce management costs by 43% over the next four years.
The force expects to keep its 828 Police Community Support Officers (PCSOs) for at least another year, but indicated this depended on continuing to receive ring-fenced grants, the report said.
By law, police officers cannot be made redundant so GMPA expects the savings in frontline officers to come from natural wastage, a recruitment freeze and forced retirement for officers with more than 30 years' service.
Three other police forces - North Wales, Strathclyde and Surrey - are also planning to implement enforced retirement, an option open to them under regulation A19 of the Police Pensions Regulations 1987.
The BBC's Political Correspondent Jo Coburn said the prime minister's official spokesman had said "individual police forces must make up their own minds" on where to make cuts.
Asked whether David Cameron was concerned about the GMP proposals, he said the government wanted to see as much of police resources as possible "devoted to the front line".
Policing minister Nick Herbert said the reduction in Greater Manchester Police's workforce would not affect its service.
"The independent inspector of constabulary has said that on average the proportion of a force that is visible and available to the public at any one time is just 11% of the total workforce and he says that is too low," said Mr Herbert.
"So the question is why, when we have had up till now a record number of police officers and staff, have we got such a low availability and visibility? And it's partly because they are tied up in red tape."
But Shadow Home Secretary Ed Balls warned that people were concerned the cuts could undermine the fight against crime.
"Every police force in the country is now having to work out the implications of the deep and immediate cuts the home secretary has demanded," said Mr Balls.
"But by front-loading the cuts in the first two years, the Tory-Lib Dem government is making it even more difficult for forces to protect the front line by finding long-term efficiency savings.
"People are rightly concerned that cuts of this scale and speed will undermine the fight against crime and anti-social behaviour and take reckless risks with the safety of our communities."
Dave Prentis, General Secretary of the Unison union, called the report "deeply worrying" for the people of Greater Manchester.
"Tory claims to protect the frontline are a sham. Losing police officers, staff and PCSOs will see crime rates soar and community safety plummet," he said.