Writing in The Sunday Times, Cameron says the Queen's speech which lays out the business of the government on Wednesday will contain plans to keep ministerial salaries at their current level for the lifetime of this parliament.
The pledge will save 800,000 Pounds a year and 4 million Pounds by 2020 -- and will clear the way for a fresh crackdown on benefits in the first fully Conservative party budget plan in 18 years, due on July 8.
UK Chancellor George Osborne has already announced a two-year freeze in welfare payments as part of his plan to shave 12 billion Pounds from Britain's benefits bill in order to eliminate the deficit by 2018-19.
In a clear signal that further cuts will be an early priority, Cameron says there is "still half of" the deficit to pay off.
"We will continue to take the difficult decisions necessary to bring spending down and secure our economy," he said.
Unveiling the pay pledge, he said: "I said five years ago we were all in this together and, five years on, nothing has changed".
He described the pay freeze as "just one step which sends out a clear signal: that as we continue knuckling down as a country, we will all play our part".
Cameron announced that the Queen's speech will contain legislation to cut the benefits cap -- from 26,000 to 23,000 Pounds -- to "make sure you're always better off in the office or factory than you are at home".
He also vowed to scrap the Human Rights Act and replace it with a British Bill of Rights to "restore common sense to our legal system".
Other pledges will give parents 30 hours of free childcare a week for three and four-year-olds, create 500 new free schools, a seven-day National Health Service (NHS) medical care and 3 million new apprenticeships.