Scammers are "preying" on people who are desperate to secure an appointment with an NHS dentist, according to leading members of the profession.
People are falling victim to fake websites offering NHS dental appointments secured through a pre-payment system, the British Dental Association (BDA) said.
The organisation has said scammers have targeted people in Essex, Devon, Merseyside, Norfolk and Suffolk, taking up to £319.10 for care.
Jacqui Nicholson, 62, from County Durham, fell for the scam after a two-year wait for an NHS dentist.
The website was promoted by someone she trusted on social media.
Mrs Nicholson paid £53 each for appointments for herself and her husband, and claims the website had an NHS logo, pre-payment options and detailed email confirmation.
She said: "It looked so real. I even Google Mapped it. It's hard to tell what's real and what's fake. Don't fall for it."
BDA chairman Eddie Crouch called for "urgency" from the Government.
In the run up to July's general election, Labour made a manifesto commitment to create 700,000 new urgent and emergency dental appointments.
"Criminals are now preying on desperate patients left with no options," Mr Crouch said.
"We need real urgency and ambition from Labour on NHS dentistry. Fraudsters will keep seeing real opportunities as long as the new Government's promises remain unkept."
The BDA wrote to Chancellor Rachel Reeves after the announcement in last week's Budget that employers' national insurance contributions would rise from April.
It said the change would "significantly add to the financial pressures" dental practices face, as the "overwhelming majority" are small businesses.
The BDA wrote: "Practices are running on empty, struggling to recruit or retain staff.
"The real reform this service desperately needs, and your party has promised, will need to go hand in hand with fair and sustainable funding."