From left to right: Maude Apatow, Iris Apatow, Paul Rudd and Leslie Mann star in the film 'This Is 40.' (Supplied) Groping Fox awkward: Leslie Mann Apatow seeks therapy for woes Is Judd Apatow Broadway bound? 'This is 40' frank and funny

Director Judd Apatow has refused to remove a joke about child murder from his new film This Is 40 following the Connecticut school massacre last week.

In the filmmaker's latest movie, a sequel to his hit Knocked Up, Albert Brooks' character says, "Line up! Line up for murder! Come on! Who wants to be killed?", while spraying his kids with a garden hose.

The children shout out "Murder me!", prompting the character to add, "All right. The kids are murdered. That will save us some money."

After 20 children were slain at Sandy Hook elementary school by suspected gunman Adam Lanza, Apatow was asked whether he would cut the line out of the movie - but the director insists the joke will stay.

He tells TheWrap.com, "I wrote this script two years ago. That line is spoken by a sarcastic father kidding with his children. In light of recent events, I understand if some people might make an unfortunate association or put it in a context in which it was not intended."

Several film premieres, including Django Unchained, Jack Reacher and Parental Guidance, as well as episodes of Family Guy and American Dad, have been scrapped following the tragedy, which claimed the lives of 20 school children and six staffmembers.