The European champions, who have lost just one of their last 32 games, had numerous scoring chances at Stadium MK, including a shot from Georgia Stanway - in her 50th appearance for England - that banged off the crossbar seconds before half time.
Alessia Russo beat Portugal 'keeper Ines Pereira but defender Ana Borges stretched for a spectacular clearance off the line during a flurry of second-half chances for England.
Lionesses captain Leah Williamson and Euro 2022 Golden Boot winner Beth Mead, who will both miss the World Cup with serious knee injuries, watched on from the stands.
Coach Sarina Wiegman will have one more friendly to firm up her World Cup starting team with England playing Olympic champions Canada behind closed doors on July 14th before kicking off their World Cup campaign on July 22nd against Haiti.
Portugal, who were late additions to last year's Euros as a replacement for banned Russia, take on the Netherlands on July 23rd in their World Cup debut.
