Prime Minister Antonio Costa announced three days of mourning, set for Monday through Wednesday.
The fatalities occurred in the Pedrogao Grande area, about 95 miles northeast of Lisbon, where about 600 firefighters have been trying to put out the fires since Saturday, Gomes said.
Portugal's prime minister has thanked the hundreds of firefighters combating forest fires that have killed at least 57 people.
"I am shocked and horrified by the many lives claimed by today's devastating fires", said UN Secretary General Antonio Guterres Sunday.
The authorities said very low smoke clouds prevented helicopters and fire planes dropping water on the flames efficiently for most of the day.
One of multiple fires that spread in Portugal sent flames sweeping across a road, which reached motorists who became trapped in their cars.
"We escaped in time, me on the tractor and he with our van", Luisilda said.
Thirty bodies were found inside cars and nearly 20 more were found next to vehicles, Portuguese officials said.
Earlier Costa said the injured included five people in critical condition as well as one child and four fighters.
Gomes said that at least 16 people were killed when their vehicles were engulfed by flames on a road between the towns of Figueiro dos Vinhos and Castanheira de Pera.
"It is a real inferno, we have never seen anything like that", the mayor of Pedrogao Grande Valdemar Alves told reporters, adding that more than 20 villages had been affected.
Several European countries have offered their assistance to Portuguese government to help mitigate the blaze.
Three people were killed and over 1,000 evacuated in the Portuguese island of Madeira due to the fierce wildfires a year ago. "I don't want to talk yet about the cause of the fire because we are facing the greatest tragedy of human lives so, what we must do now is to calmly provide all the resources to fight the fires".
Fire fighting aircraft were being sent from France and Spain, the EU's humanitarian aid commissioner Christos Stylianides said.
In Kazan, Russia, Portugal's national soccer team wore black arm bands and stood for a moment of silence with the Mexican team in solidarity with the forest fire victims.
French President Emmanuel Macron tweeted: "Solidarity with Portugal, hit by bad fires". Mariano Rajoy has tweeted that he is "overwhelmed by the tragedy at Pedrogao Grande".
"This tragic situation took place in only one of the fires, particularly at a road next to it", Costa told the media.