The Prime Minister's office (PMO) conveyed this to the Chief Minister's office today, CMO sources said.
The inaugural function of the 13-km Aluva-Palarivattom corridor will be held at Aluva in Ernakulam district.
Kochi Metro, which secured the green signal from rail safety panel, had begun service trials recently on the corridor.
A controversy had erupted over the inauguration after BJP Kerala leadership had alleged that the state government wanted to inaugurate the project by this month end when the prime minister would be away on a European tour.
The state government had recently given clearance for extension of phase II of Kochi Metro from Jawaharlal Nehru stadium to Infopark.