The London Fire Brigade criticised Peppa Pig for using the term "fireman" instead of "firefighter" in an episode called The Fire Engine.
"Come on @peppapig, we've not been firemen for 30 years," it tweeted.
"You have a huge influence on kids & using out of date stereotypical gender specific wording prevents young girls from becoming firefighters."
According to Government statistics, 5.2% of firefighters in England were women in 2017.
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Piers Morgan scoffed at the suggestion that Fireman Sam, which first hit UK television screens in 1987, was also culpable after it came under similar scrutiny for its use of gendered language.
The TV presenter tweeted: "If women are being 'put off' joining the fire service becauseFireman Sam - A CARTOON CHARACTER - supposedly 'perpetuates male stereotypes' then can I politely suggest these women probably don't have what it takes to fight fires."
Championing their #FirefightingSexism campaign, the London Fire Brigade responded by saying that young girls "think they can't be firefighters because children's TV continues to use outdated language".
"If you respect our work, then get our name right," the brigade tweeted.
After one Twitter user pointed to character Firefighter Penny Morris in response to the fire service's criticism of Fireman Sam, London Fire Brigade said her involvement is "completely devalued" by the show's name.
"Sadly Penny's involvement in the show is completely devalued by the constant use of the outdated term fireman in the catchy theme tune, title and on all merchandise," the fire brigade tweeted.
The debate continued on ITV's Good Morning Britain, with Morgan sarcastically telling viewers: "Postman Pat - he can't be a postman any more. What is he, a postperson? Postperson Patricia?
"And you can't have a black and white cat because that's racist."
Southampton footballer Charlie Austin agreed with Morgan's view, tweeting: "This programme is not sexist... it's Fireman Sam next we will be talking about postman pat and bob the builder."
Meanwhile Celebrity Big Brother star Casey Batchelor described the idea that FiremanSam is sexist as "ridiculous".
However West Yorkshire Fire and Rescue firefighter Dave Walton said he "fundamentally disagrees" with criticism from people such as Morgan.
He tweeted: "The show is aimed at CHILDREN, specifically at a time of life when they are clearly influenced by what they see on TV.
"That's where we can make a difference for the future."
Earlier this week, London Fire Brigade commended the release of a new firefighter Barbie, wearing the service's uniform.
It tweeted: "She's been toying around with different careers but for her 60th anniversary she's smashed another glass [plastic?] ceiling by becoming Barbie the firefighter! AND she's donning our gold kit too.
"Great to have her #FirefightingSexism support #ThisGirlCan."
A statement from production company Mattel read: "We have enormous respect for all firefighters and the work that they do; we are committed to representing their work in the most appropriate way through our entertaining show for children.
"Fireman Sam is a much loved and iconic brand and we are constantly evolving to make sure that we stay true to the show's heritage as well as representing the world that children see around them today.
"The team are always referred to throughout the show as 'firefighters' except Sam who has not evolved his title in his role as the show's namesake.
"We recognise the need to stay relevant and we continue to evaluate the show to ensure Sam remains an aspirational hero for generations of pre-schoolers."