Dentists spoken to in Invercargill said they had stopped taking on patients, one surgery not having enrolled a patient in two years.
The Dental Association has tried, with some success, to get graduates to head south but there is still a shortage.
There appears to be no hope of a quick end to the shortage as demand for services continues to increase.
Toothworks is one Invercargill clinic which is full.
"Our books have been closed for a couple of years now so we don’t take on any new patients," a Toothworks spokeswoman said.
"All we can do is refer people to Southland’s emergency dental service, but that just covers people who have toothache that don’t qualify for treatment at the hospital."
John Harris Dental was booked out until July and had been full since last year due to a long-standing dentist leaving the practice, a spokesperson from the surgery said.
Mr Harris had to take on a load of his colleague’s patients, which forced the practice "to make the tough decision of not taking on any new patients".
"John has been here a long time and built a large client base from all around Southland.
"We’ve got to be loyal to our existing patients because they’ve been loyal to us."
Dentist on Kelvin was booked for months in advance and would only take "family members from the same household" of existing clients for emergency services, the practice said.
Invercargill orthodontist and Southland Dental Association president Dr Jennifer Lee agreed the reason practices could not take on new patients was because there was a shortage of dentists in Invercargill and that it was "difficult to turn patients away, but the dental practices were trying their best within their own capacity".
The Dental Association had tried to mitigate the shortage of dentists in Invercargill by hosting a week for final year dental students to come to Invercargill and observe the local practices.
"We recruited quite a few dentists from this and we also talked about participating in the careerfest to encourage more secondary school students to pursue careers in dentistry," she said.
Invercargill residents have resorted to travelling to Queenstown and Dunedin for treatment due to not being able to get into dentists in Invercargill.
Dr Lee urged locals to use the emergency dental service in the meantime as there was a dental roster in place for patients who were seeking treatment for acute pain.
