Activists and democracy supporters said Tuesday's march from Thammasat University to Government House to call for early elections will go ahead as planned.
"The plan remained unchanged. We will gather for a rally at 7am tomorrow," Rangsiman Rome, a leader of the Democracy Restoration Group, said at the university on Monday.
The activists will walk from the Tha Phra Chan campus to Government House on the fourth anniversary of the coup, which brought Gen Prayut Chan-o-cha to power.
Mr Rangsiman promised a peaceful protest on Tuesday and said the walk to Gen Prayut's office was necessary to pressure the government for a poll after it has been delayed since the National Council for Peace and Order (NCPO) took power.
"We have to go to Government House to let Khun Prayut and Khun Prawit know what the people want," he said, referring to the prime minister and Deputy Prime Minister Prawit Wongsuwon.
"We might not be a majority but I'm sure that a large number of people want an election to be held."
Traffic police have advised motorists to avoid roads around the campus and Government House from 7am on the rally day although Metropolitan Police Bureau commissioner Pol Lt Gen Charnthep Saesawet was confident that the situation will be under control.
Police will be deployed along the routes where they march, he added.
Security authorities were also deployed outside the university, which is used by protesters as an overnight rally base. The university closed the main gates from Sanam Luang before other activities forced it to reopen later.
NCPO spokesman Maj Gen Piyapong Klinpan said the regime did not expect a long protest on Tuesday as it could end by noon after the demonstrators lodged their demands to the prime minister.
The three demands of the demonstrators are: the general election must be held in November, the NCPO must be dissolved to ensure the polls are free and fair, and the military must stop backing the NCPO and return to the barracks.
The area outside Government House has been sealed to prevent protesters from going inside.
Military police patrol the area around Government House on the eve of a planned rally by election supporters. (Photo by Tawatchai Kemgumnerd)
