The ban refers to “racist, extremist or violence-promoting symbols, words or drawings" and also covers earrings, bracelets and rings, Portugal’s police force said in a statement.
Police gave no estimate for how many officers might be affected by the ban, which coincides with increasing racist violence in the country.
The Council of Europe, a European human rights organisation, referred in a 2018 report to numerous grave accusations of racist violence against Portuguese police, while complaints to the country’s anti-discrimination commission rose by a quarter last year.
The move comes after Marcelo Rebelo de Sousa, Portugal’s president, declared in August that there would be “zero tolerance” of racism in the country as authorities launched an investigation over a number of email threats, allegedly sent by a far-right group.
The threats targeted several people, including two black lawmakers who were told to leave the country and threatened with murder.
Earlier this month, the European Network Against Racism (ENAR), an EU-wide network of non-government organisations, called for an “urgent institutional response” from Portuguese authorities and the EU towards racism in the country.
“In recent months, there has been a very concerning rise of racist attacks of the far right in Portugal, targeting human rights defenders from racialised minorities,” the ENAR said.
It added: “We call for an urgent response from Portuguese authorities to effectively protect racialised groups from racist crime, ensure proper investigations and prosecution of perpetrators, and sanction those inciting hatred and violence.”
The network also linked the attacks to Portugal’s 2019 general election, which saw the far-right party Chega gain a seat in the country’s parliament.
Former football commentator Andre Ventura’s victory for the party won the first seat in parliament for the far-right since the country’s dictatorship ended in 1974.
Additional reporting by Reuters