Communications Minister Anika Wells is under fire for slugging taxpayers almost $100,000 for flights to New York where she spruiked Australia’s world first social media ban.

Officials at a Senate estimates hearing confirmed $94,828 had been spent on flights for the minister and two staffers to attend the United Nations General Assembly in September.

Opposition Leader Sussan Ley blasted the cost of the airfares and said Wells should have been “focusing on her day job” as Australia was dealing with the deadly Optus triple-zero outage at the time of UN summit.

“Australians were anxious about their emergency services network and the crisis was well and truly ongoing,” Ley said in Sydney on Thursday.

“She chose to hop on a plane and go to New York for a job that cost the Australian taxpayers nearly $100,000.”

Wells defended spending public money to get to the UN to tout Labor’s social media ban for under-16s, which takes effect next week.

“That event fuelled a global momentum in this space. You have seen a number of different jurisdictions come out … to announce they’re going to do exactly what Australia is doing,” she told the National Press Club on Wednesday.

Acting Prime Minister Richard Marles said the flights to the US were within government guidelines and travel was changed last-minute to juggle the Optus outage.

“The important point here is that Anika was focused on what is a really significant initiative which will be coming into force next week,” he told Sky News.

Nationals leader David Littleproud said ministers are aware of travel expenses before they jetted off, and it was usually approved by the prime minister.

“I don’t begrudge ministers travelling internationally, particularly for forums that are important, but it’s how it’s done,” he told Sky News.

Greens communications spokeswoman Sarah Hanson-Young said Wells should have cancelled the whole trip amid the backdrop of the Optus crisis at the time.

“I still stand by that … sometimes you’ve got to choose to stay home” she told Sky News.

Emma Mason, the mother of 15-year-old Tilly who took her own life after being bullied online, spoke at the UN conference and called it “repugnant” that Wells was pushed on the trip’s cost.

“The question alone was repugnant and then to be asked twice, worse,” she said in Canberra.

“We have to be putting out best foot forward and projecting Australia as a country of importance.”

-AAP