Police may summon the organisers of the "Sarawak Freedom and Independent Walk" for investigations into the call for the state to secede from Malaysia.
Inspector General of Police Tan Sri Khalid Abu Bakar said police were expecting about 700 people to attend the gathering in Kuching on Wednesday.
"We are monitoring their activities and the message they are disseminating. We won't hesitate to take action against them.
"To call for Sarawak's secession is serious. We will summon the organisers if need be," he told reporters here.
In Kuching, a large gathering, organised by Sarawak Dayak Iban Association and Sarawak for Sarawakians movement, took place to celebrate the day Sarawak was granted independence by the British colonial rulers on July 22, 1963.
Bukit Aman had urged the organisers to call off the gathering alleging that some quarters were using it to push for Sarawak's secession from Malaysia.
Khalid was reported saying that police received information that certain individuals were planning to use slogans "Sarawak For Sarawakians" and #722 Sarawak Freedom and Independent Walk to provoke and incite others in seeking Sarawak's secession.
He said such actions were against the Federal Constitution.