Protesters throw stones and Molotov towards riot police in the center of the capital, as clashes broke out during a 24-hour strike in Athens on March 16, 2023. AFP
The Prime Minister's office said police chief Constantinos Skoumas had been discharged less than two months after being confirmed at the post.
No specific cause was given for prompting the change, which comes as police face widespread public criticism for their handling of protests over the February 28 tragedy in which 57 people were killed when two trains collided.
"The appointment of a new police chief aims (to introduce) a more positive and efficient implementation of modern police operational plans on citizen safety," the PM's office said.
In the latest protest on Thursday, a riot police squad was filmed charging and striking peaceful demonstrators at the central Syntagma Square in Athens.
A police tow truck was also filmed ramming a group of demonstrators trying to block an Athens street with garbage bins, sending one demonstrator flying to the ground.
The train disaster has sparked weeks of angry and occasionally violent protests and has piled major pressure on the conservative government of Prime Minister Kyriakos Mitsotakis ahead of elections expected in May.
Most of the victims were students returning from a long holiday weekend.
"We will learn from our mistakes," Mitsotakis said during a campaign stop in Athens on Saturday.
"A mistake becomes a fault only if it is repeated."
Greece's transport minister resigned after the disaster, and the stationmaster on duty during the accident and three other railway officials have been charged and face a possible life sentence.
But railway unions had long been warning about problems, claiming the network was underfunded, understaffed and accident-prone after a decade of spending cuts.
Acting Transport Minister Georgios Gerapetritis has said rail services -- which were suspended after the accident -- would gradually resume from March 22.
But safety concerns remain high.
Gerapetritis and former transport ministers will appear before a parliamentary committee on March 20 to answer lawmakers' questions on the tragedy.
The minister on Saturday said he would then travel to Brussels during the week for talks with EU officials on "technical assistance" to improve safety.
Train services will be fully restored before April 16, and the government aims to introduce automated safety systems by the end of September, he said.