(CNN) -- It started as a hefty severance bonus for lawmakers -- quietly tucked into a Kenyan finance bill passed last week.
A few days later, angry demonstrators gathered outside parliament offices in the capital of Nairobi. They carried placards reading "greedy hyenas" and hollered "thieves" as members of parliament dashed into their offices.
Kenyan parliament members, among the highest paid in the continent, voted for a send-off bonus of about $120,000 each for when they leave office.
They already make about $10,000 in salary and tax-free allowances per month.
An average Kenyan makes about $1,800 annually, and would have to work for 67 years to earn the bonus amount.
The proposal prompted calls for protests on social media as Kenyans implored the president to veto the bill, which passed days after doctors' strikes for higher wages.
"Our parliament members are pigs," said John Kamau, 32. "Our doctors and teachers were on strike for weeks. The government said there were no funds to meet all their demands. And yet they have funds to award themselves these packages?"
It was unclear how the proposed bonuses would be funded, but lawmakers called for a 10% increase in taxes in the same parliament session.
Hours after protesters took to the streets, President Mwai Kibaki vetoed the proposal Tuesday night.
"The president objected to the amendment on the grounds that it was first unconstitutional and that in the prevailing economic circumstances in the country, it is unaffordable," the president's office said in a statement. "Coming shortly after the increment of salaries for teachers and doctors, the severance pay for parliamentarians would lead to an unsustainable wage bill at a time when the country requires massive resources to ... meet other competing demands."
Prime Minister Raila Odinga, who is a presidential contender in next year's election, said he is against the bonus.
The Kenyan National Assembly comprises 224 seats, but not all legislators voted for the bonus on October 4.
Some legislators rejected the proposal and applauded the president's decision.
"The president's decline to assent to the finance bill confirms that the citizens' voice matters," said Martha Karua, a parliament member and presidential candidate. "Let's keep vigilance and together slay impunity."
The proposal violates the constitution, which mandates that parliament should not set its own pay, according to human rights groups.
"It's very telling that they can hike their bonus at night quietly and teachers had to strike for three weeks," said Edward Mburu, 38, who lives in Nairobi. "You can see we are dealing with selfish people. People are angry ... I hope it translates into conscious voting."
The east African nation is scheduled to hold elections in March. It will be the first general poll since postelection violence left hundreds dead in 2008 after disputed results.
CNN's Lillian Leposo contributed to this report.