Non-resident citizens in Portugal – both Portuguese and foreigners – are obliged to appoint a tax representative, provided that they are subject to tax relations in the country.
If they do not, they will not be able to conduct any business or complain or challenge decisions of the tax administration.
For the Portuguese, it is a mistake to declare that they are resident in Portugal when they reside outside the country more than 183 days a year.
Article 19 of the General Tax Law states:
6-taxable persons residing abroad, as well as those who, although resident in the national territory, are absent from this for a period exceeding six months, as well as legal persons and other entities legally assimilated that cease the activity, shall, for tax purposes, designate a representative with residence in national territory.
7-Regardless of the applicable sanctions, depends on the designation of representative in accordance with the preceding paragraph the exercise of the rights of taxable persons referred to therein before the tax administration, including those of complaint, appeal or challenge."
Note: it does not exempt the consultation of the legislation in force.