Protests against soaring short term tourist rentals and rising rents -- issues which have drawn popular ire in several other countries -- drew hundreds of people in Lisbon on Saturday, Lusa news agency reported.
"Rein in rents, stop expulsions" and "enough tourism rentals" were slogans brandished by those joining the march in the capital, which was attended by several hundred people.
A smaller demonstration in the northern city of Porto saw a few dozen people turn out.
"People are becoming increasingly aware of the extent of the problem -- but political measures are needed to turn things around," said Ana Gago of the "Stop despejos" (stop expulsions") pressure group.
"Real estate speculation is driving people out of the centre of town. Property can't be a business -- it's an essential good," insisted another protester, Joana Dias.
Marchers demanded the authorities limit the amount of properties being withdrawn from the long-term rentals market for use as more lucrative tourist versions on online sites, such as Airbnb.
Organisers said some 15,000 such properties are being advertised on rental platforms in Lisbon -- around three quarters of them purely for tourist use.
A similar scenario in other cities, not least Paris, has also led to protests. Earlier this month the Paris city council member in charge of housing said he would propose outlawing home rentals via Airbnb and other websites in the city centre, accusing the company of forcing residents out of the French capital.
Business daily Jornal de Negocios said around a third of apartments in Lisbon's historic centre have been given over to tourism.
Housing rights activists are critical of measures put in place by the former conservative government during the 2011 financial crisis in order to attract foreign investors to the Portuguese real estate sector.
But the current socialist administration has said it not planning to overturn those measures, which include tax sweeteners for foreign retirees and golden visas for non-EU property investors.
After the financial crisis real estate prices in Portugal have shot back up, adding 5.6 percent in 2015-2016 and then another 9.2 percent last year, according to a recent report by Spain's Caixabank.