Health Protection Scotland (HPS) said NHS Tayside had seen a rise in the number of cases in the second half of 2013.
The agency said this had been reported particularly in young heterosexual people aged between 15 and 25.
Their weekly report revealed that information regarding the rising number of cases had been sent to doctors and other organisations in an effort to encourage people to come forward for testing.
Failure to treat syphilis can lead to serious complications, including heart problems.
Various measures have already been taken to try to prevent and control the growing number of cases.
This includes enhanced surveillance to identify any links between the patients affected.
Experts are also making sure that positive test results are followed up and treatment started, as well as creating extra capacity in sexual health clinics.
HPS said: “The board is urging anyone with symptoms or who may be at risk of infection to attend sexual health services or their GP to be tested.
“Tayside residents seeking advice can speak with the sexual and reproductive health team at Ninewells Hospital.”
The board would normally expect to see only a couple of cases of syphilis in the heterosexual group each year, but has seen a five-fold increase on this in the last six months.
Kirsty Licence, a consultant in public health medicine, said: “NHS Tayside has seen an increase in the number of cases of syphilis, particularly in young people aged between 15 and 25.
“Syphilis is a bacterial infection that can be transmitted through unprotected sex including oral sex.
“People with syphilis may develop a painless ulcer in the genital area or in their mouth. They may also develop a rash over their body, palms of the hands and soles of the feet.
“These symptoms may disappear without the person being aware of them, but the person will remain infected and risk infecting other sexual partners.”
Dr Licence said about half of people having sexual contact with an infected person would be likely to pick up the infection themselves. “If syphilis is not treated, it will progress and can cause serious damage to the heart, arteries and the nervous system,” she added.
Dr Licence said syphilis could be successfully treated with antibiotics. “The best way to prevent syphilis and other sexually transmitted diseases is to use a condom,” she added.
Earlier this year, NHS Lanarkshire also reported a rise in cases of syphilis among people under 25. During 2012, a total of 17 cases of syphilis were diagnosed by the NHS Lanarkshire Sexual Health Service. But between 1 January and 24 June alone, they reported 19 cases.