The Prime Minister has already told MPs that he will not allow the pay and bonus total to rise in the taxpayer-owned bank but his critics have argued that would still enable individual bankers to earn more year-on-year as the number of workers in the Edinburgh-based institution has fallen by some 40,000 since the £45 billion taxpayer bail-out in 2008.
During his visit to the World Economic Forum in Davos, the Prime Minister went further than his previous statements, saying he wanted the level of pay and bonuses to come down per person as well as overall.
He said: "With our particular responsibility for RBS, I can tell you that I don't only want to see the level of pay and bonuses come down overall, I want to see it come down per-person, per-capita as well."
Earlier this month, it was suggested RBS - like other big banks - was expected to invoke an EU rule that allowed it to pay bonuses up to double an employee's salary, which is twice the normal rate, if approved by the shareholders.
It has been reported the agency responsible for managing the public stake in RBS is considering abstaining in the vote that would allow this.
The PM also claimed new European rules on bankers' pay, which the UK Government opposes, could exacerbate the riskiness of banks.
"This European directive... in some ways might make things worse because you could see rates of pay go up," he said.