Amid challenges to its own journalism - and its proprietor Jeff Bezos - the Washington Post has flown the flag for the role of newsmedia in a stirring Super Bowl commercial.

The 70-second spot before the fourth quarter paid tribute to three "lost in service" journalists including its own Jamal Khashoggi. Narrated by actor Tom Hanks, it included pictures and footage from news stories from World War II to the civil rights movement, the Moon landing, natural disasters and terrorist attacks.

"There is someone to gather the facts, to bring you the story, no matter the cost," says the Hanks voiceover.

The Post used the spot to pay homage to journalist Austin Tice - captured in Syria in 2012 and whose fate remains unknown - photographer Marie Colvin, killed by the administration of Bashar al Assad in Syria, and Khashoggi, who was murdered while visiting the Saudi consulate in Turkey late last year.

News Media Alliance innovation vice president Michael MaLoon says the ad's true focus is on the value journalists bring to the audience. "The message is not that journalists are heroes or that news is infallible, but rather, that we are better for having access to news."