In four days, 20-year old Kaylen Ward estimates she has raised more than $700,000 for the victims of Australia’s bushfire crisis – by sending nude photographs of herself to anyone who donates more than $10 to one of her chosen charities and sends her the receipt.

The California resident has worked as a nude model since August 2019. While vacationing in the Caribbean she says she fell into a “rabbit hole” after reading about the unprecedented fires that are raging along Australia’s eastern and southern coastlines.

“I donated $1,000 myself,” she tells Guardian Australia. “I had a substantial amount of followers, maybe 30,000 at the time, and I thought that a lot of my followers would pitch in and send in some donations for the wildfires.”

At around 10pm on 3 January, Ward tweeted a nude image of herself – with an angel emoji acting as a modesty strip – alongside a list of charities her followers could fund. That evening she raised more than $7,000. “The next morning I woke up and it had gone absolutely viral and I was flooded with messages. It quickly just blew up and went upwards of $100,000 before I knew it.”

Ward’s original tweet has now been retweeted 77,000 times and she has started calling herself the Naked Philanthropist. “Not all heroes wear capes,” has been one of the most common responses to her efforts.

Australia’s bushfires have drawn a number of high-profile charitable contributions. Comedian and Instagrammer Celeste Barber has raised more than A$40m to support the New South Wales Rural Fire Brigade, while celebrities including Kylie Minogue, Pink and Nicole Kidman have made individual contributions of A$500,000.

Although she has not tallied the exact total yet, Ward believes her donation drive could exceed $700,000. “I have a girl that’s doing the analysis on it and she’s calculated that I’m getting about 10 legitimate verified DMs per minute,” she says. “And that’s only saying everybody donated at least $10, that’s not even calculating the average amount, because I’ve had donations of $5,000 … I feel that the number is way beyond that.”

The cause is a personal one for Ward, who was affected by the Carr and Camp fires in northern California in 2018. “I got to see first hand how fires like that can affect people and how devastating they are,” she says. So far, Australia’s bushfires have burned through more than 8.4m hectares. “To put [the California fires] up to scale with what’s happening in Australia right now, it’s not even comparable.”

Ward explains that she is offering something people were already prepared to pay for. “I already use my Twitter platform to make money by selling nude photos … I have a loyal fan base who buys content from me and that’s how I pay my bills.”

However, she was unprepared for the “overwhelming” amount of attention she has received and is struggling to keep up with the demand. “I’m still a little bit in shock about how much positivity I’ve received from this.”

Ward’s efforts have inspired other sex workers to offer naked photographs in exchange for donations to Australia’s bushfire relief funds.

Katie Day, a Vancouver-based sex worker, says she saw the Naked Philanthropist’s tweet and “thought it was a really great way to encourage people to donate”. She tweeted on 6 January that she was joining Ward’s efforts. She hoped to raise a couple of hundred dollars, and has already surpassed that goal, raising more than $1,000 in 24 hours, mostly from “people I’ve never heard of before”.

Ward is flattered that others are following in her footsteps. “I think what’s important is raising as much money as possible. If people are doing that successfully it makes me so happy.”

But not all of the attention has been positive. Since posting the viral tweet, Ward has faced criticism for previous posts she has made on social media. “Mostly it’s not people saying anything negative about what I’m doing. It’s more people trying to dig and find out who I am, and try to find out anything they can about me that’s negative. It’s become almost an obsession to a few of these people.”

Ward has also been upset that her Instagram account, which had more than 60,000 followers and was a significant source of revenue, has been deleted. “Every time I try to make a new account it’s deactivated, and what’s concerning is there are a few fake accounts who are impersonating me that haven’t got deleted. People are stealing my identity through Instagram.”

Ultimately, Ward remains upbeat about the situation. “People are always going to have their opinions especially if you’re in this line of work” she says. “If you’re doing it for a good cause and you know deep down you’re a good person, never let anybody get to you or make you feel that you’re less-than.

“It is a little bit overwhelming that I’m so vulnerable and everybody’s staring at me. Especially because I’m naked on the internet right now. [But] I’m only one person and I’m helping so many other people, so I’m not the most important thing right now.”