The MCAP's manifesto defines the organization as a "peaceful non-partisan movement" that brings together citizens and groups that are dissatisfied with the country's problems, and are willing to protest until they are solved.
"We want to bring together all the Portuguese voices... to gather as many people as possible, so that all of them have their voice. [We want] to amplify the population's discontent, which is real," MCAP's Ana Vieira told Publico newspaper, also stressing that "the protest's main objective is to get citizens to be heard by Portuguese rulers."
Portugal's Public Security Police has prepared a 20,000-man team to monitor 25 protests in 17 cities.
The rallies will start in the morning and culminate with a major afternoon demonstration at the parliament in the country's capital, Lisbon.
The Portuguese movement is pushing for an increase in minimum wage, a review of unemployment benefits, a reduction in disparities in retirement pensions and termination of "millionaire" pensions.
In addition, Yellow Vests request a reduction of both the value-added tax (VAT) and the tax applied to small companies, the suppression of fuel taxes, and the end of bank commissions, among other claims.
Portugal's conservative President Marcelo Rebelo de Sousa, who has publicly appealed for calm, hopes the Yellow Vest protests will be peaceful.
"The situation in Portugal is different from that in France, where they had always bloody revolutions. Portugal had a Carnation Revolution... we know complaint, indignation and protest must be expressed peacefully," said Rebelo de Sousa.
The country's socialist Prime Minister Antonio Costa, for his part, said he expects the demonstrations to take place "with calm, tranquility, and respect for legality, as is [Portugal's] tradition."
The Yellow Vests movement is an uprising which started in France, in Oct. 2018, to reduce and remove fuel taxes. Subsequently, the French Yellow Vests expanded their demands to include the increase of the purchasing power of the middle and lower classes, the elimination of austerity policies and the resignation of President Emmanuel Macron.
Once converted into symbols of contemporary citizen rebellion, Yellow Vests protesters have expanded their scope of action
According to The Guardian, protesters wearing yellow vests have also been seen in Belgium, Bulgaria, Canada, Germany, Greece, Poland, Serbia, Spain, Sweeden, Turkey, Poland and the United Kingdom.