Naughty Dog, creators of the popular post-apocalyptic game The Last Of Us, told gaming site Kotaku that the error was down to "an artist's mistake".
The offending numbers appeared on an in-game poster for "pest control".
The update, version 1.02, has now changed the numbers and addressed other crash and connectivity issues.
The game's creative director Neil Druckmann told Kotaku: "That was an artist's mistake. What happened was they put some phone numbers in the game and then they thought they could just change the area code to 555, then it's invalid, because it's what they do in movies.
"But I guess that doesn't work when you have a 1-800 in front of it. It was just an honest mistake."
Sharp-eyed gamers who had spotted the numbers and rung them were surprised to hear salacious recorded messages.
The Last Of Us, created exclusively for the Sony PlayStation 3, was launched in June.
But the sex-chat-lines gaffe is not the only controversy surrounding the game.
It features a post-plague future world, a violent survivor called Joel, and a teenager called Ellie who some observers believe bears a close resemblance to the Canadian actress Ellen Page, star of films such as Juno and Inception.
And Ms Page is not happy about the similarity.
In an Ask Me Anything question-and-answer session on the Reddit website last week, she wrote: "I am actually acting in a video game called Beyond: Two Souls, so it was not appreciated."
The Ellie character in The Last of Us is played by actress Ashley Johnson.
A video-game maker has had to release an update to their latest title after real-life sex-chat-line phone numbers were discovered in the artwork.