Experts say the accounts use images and stories about the 50-year-old to specifically target middle-aged women perceived to have poor digital literacy skills.
It comes as the actor has warned his fans to be wary of so-called romance scammers, reiterating that he has only one verified social media account on Instagram.
A search for "Martin Henderson" returns hundreds of fake profiles on Facebook alone, which use images from his official Instagram account as well as publicity shots for his Netflix hit Virgin River.
The page transparency details of the accounts reveal they are run from all over the world, with many listed as being operated from Nigeria.
The accounts post messages in a bid to create engagement with followers.
The account owner then typically engages personally with followers in the comments, before suggesting private chats through direct messages or even through other communication channels.
"At this point I have to post this here," one post reads. "My lovely fans…I lost one of my house [sic] in Los Angeles California because of the fire… brake [sic] down I'm in pain fans…Your warm messages will really help me."
"Sending healing prayers," one follower commented, which prompted the fake Henderson to suggest they communicate privately.
"Thank you for your care!! You can send me direct message your warm message will really help me."
Other posts have tried to entice fans with supposed news Henderson collapsed while on stage and that he has been called ugly and is set to lose his part in Virgin River.
"Sad news came in earlier today stating that the Actor Martin Henderson collapsed while performing on stage," one post's caption reads.
"He needs all the prayers he can get to get back to his feet kindly say a prayer for the singer when you see this post."
In the comments on some posts, multiple fake Henderson accounts compete for the attention of female users.
Dali Kaafar, executive director of the Macquarie University Cyber Security Hub, said those operating the profiles specifically target the potential victims they engage with.
"It is those identified as potentially lonely, or widowed, or sometimes even recently divorced," he said.
"These individuals would be viewed as emotionally vulnerable and in need of some sort of friendship or companionship."
Professor Kaafar said scammers will often spend weeks or even months building up a relationship before they start asking for money.
"It could be things like covering travel expenses or emergency medical bills or for some sort of urgency, or for investment."
The warning rings true, matching the experience of the 47-year-old US divorcee who sent $375,000 to someone she thought was Henderson over a two-year period, as reported in the NZ Herald.
She was in daily contact and even moved to NZ to be with who she thought was Henderson.
Ken Gamble, a cybercrime investigator at IFW, said whenever a new celebrity gains prominence, scammers will make accounts.
He said scammers will often be based in poorer countries with lax cybercrime laws.
"You need to look out for the language used," he said. "You can normally detect whether English is their first language or second language."
He named Nigeria and Eastern Europe as particular hotspots and said such operations are often run on a huge scale with multiple people working in a call centre-type environment.
AAP FactCheck contacted Martin Henderson but did not receive a response.
Meta pointed AAP FactCheck to a recent online post about how to protect against romance scams on social media.
In particular, the company said to be cautious with new contacts, to verify identities and to be sceptical of declarations of love if you have never met.
