Ronaldo, 33, was awarded the Grand Cross of the Portuguese Order of Merit three years ago, after leading his nation to a surprise triumph at Euro 16.
Awarded to those who represent the country with distinction and 'sacrifice in favour of the community', Ronaldo may see his honour revoked after accepting a fine of 18.8 million upon the admission of guilt of image rights fraud.
"The law is very simple: it is up to the chancellors of the national orders to see if anything has happened that could lead to the loss of an honour," President Marcelo Rebelo de Sousa said.
This means it would be the current chancellor of Portugal's civil Order of Merit, one of several branches of the country's honours system, to decide whether the 33-year-old's conviction is enough to strip him of his honour.
"We should let those with the legal power to decide to do so and see whether the law applies or not in this case."