"Our mission... is going to enforce peace, stabilization," said MP Nelson Koech, who heads parliament's Defense, Intelligence and Foreign Relations Committee.
"We must secure our region," he told parliament on Wednesday, adding that the mission would cost 4.4 billion shillings ($36.5 million) for the first six months.
"If it escalates and there is a spillover of our time there, it will go up to 5.5 billion to six billion (shillings)" he said.
MP Koech said talks were under way with the UN and other organizations to secure international financing for the EAC force.
Some MPs questioned footing the bill for the deployment at a time when Kenyans are suffering deep economic hardship including a cost-of-living crisis and drought.
A UN force, known by its French acronym MONUSCO, is already operating in the DRC, where it has been engaged in operations to suppress the M23 Insurgent group.
The M23 has won a string of victories against the DRC's army in North Kivu province in recent weeks, dramatically increasing the territory under its control.