Amid generally positive reviews of his jabs at Hollywood and #OscarsSoWhite, the host of Sunday’s Oscar ceremony, Chris Rock, is being taken to task for some of his material involving Asian-Americans.

Introducing the accountants from PricewaterhouseCoopers, which tabulates the vote results, Mr. Rock instead brought onstage two boys and a girl of Asian heritage, whom he named Ming Zhu, Bao Ling and David Moskowitz. As they clutched briefcases, they visually illustrated the stereotype that Asians are diligent workers who excel at math.

“If anybody’s upset about that joke, just tweet about it on your phone that was also made by these kids,” Mr. Rock added, a punch line interpreted as a reference to child labor in Asia.

But that seeming awareness of how fine the line was between satire and slur, only added insult to injury, Lowen Liu wrote on the Slate site. “Even if the second beat tries to turn things around, it still allows the teller to make an Asian joke and then excuse himself from the telling. He pulls the rug out from under the audience only to hide underneath it.” (Sacha Baron Cohen, in character as Ali G, later also made a swipe — involving Minions and “l(fā)ittle yellow people” — that many found offensive.)

Constance Wu, the “Fresh Off the Boat” actress, tweeted her disappointment: “To parade little kids on stage w/no speaking lines merely to be the butt of a racist joke is reductive & gross,” she wrote.

So did the actor Jeffrey Wright, who tweeted that the “joke needed recalibrating,” among other more stringent comments.

In a new study, the University of Southern California Annenberg School for Communication and Journalism found that at least half of the movies, television and streaming series released over the last two years had no speaking or named Asian-American characters; when they are represented, it is rarely in leading roles.

Even well-known Asian-American actors like Ken Jeong are still asked to do stereotypical accents, as he and others detailed in a recent New York Times story. “It’s getting a little bit better, but it’s just not great,” Mr. Jeong said of onscreen representation. “We have a ways to go.”

Asian and Asian-American performers, like the South Korean actor Lee Byung-hun and the TV star Mindy Kaling, were on hand as Oscar presenters or prominent guests on Sunday. And the academy president, Cheryl Boone Isaacs, called on her colleagues to “take action” because “our audiences are global and rich in diversity, and every facet of our industry should be as well. ”

But many critics said Mr. Rock’s jokes seemed like a missed opportunity to highlight the fact that inclusion goes beyond black and white. (There were no jokes aimed at Latinos, but there was also no indication by the awards show that they were proportionately missing from the big screen, though the statistics say they are.)

The actor Daniel Dae Kim tweeted that the first reference to any ethnicity other than black took 30 minutes, when “someone mentions ‘pho.’ I thought #diversity was more than that.”

As the writer Mina Kimes noted on Twitter, the joke “ would’ve stung less if there were more Asians on stage tonight.”

In response to the ceremony, the writer Jaya Sundaresh created her own social media movement, urging followers to use #onlyonepercent “to reflect the fact that Asian Americans have rec’d only 1% of Oscar noms in its history.”

An antidote to the one-liners came from the Pakistani journalist and filmmaker Sharmeen Obaid Chinoy, who picked up her second Oscar for documentary short, this time for “A Girl in the River: The Price of Forgiveness,” a film about an 18-year-old girl who survived an attempted “honor killing,” only to see her attackers set free.

“The Pakistani prime minister said he would change the law on honor killings after watching” her film, Ms. Obaid Chinoy said in her acceptance speech. “That’s the power of film.”