Research released annually by the Communicable Disease Surveillance Centre, Northern Ireland (CDSCNI) also shows that an outbreak of syphilis which began in early 2001 continues unabated.

Consultant epidemiologist Dr Neil Irvine said the figures show people are " continuing to ignore the basic advice".

The research looks at STI cases in 2006 and found startling increases in the main infections including syphilis, gonorrhoea, chlamydia and genital herpes.

The only positive news, on today's World Aids Day, was a slight drop in the number of new cases of HIV on the year before.

Among the key findings were 43 new cases of syphilis - up 13% on the 38 reported in 2005.

The findings also showed:

? 1,979 new cases of chlamydia - up 21%

? 274 new cases of genital herpes - an increase of 15%

? 195 people diagnosed with gonorrhoea - an increase of 7%

? 57 new cases of HIV infection - down by seven.

Dr Say Quah, an expert in sexually transmitted diseases at the Royal Victoria Hospital in Belfast, said anyone who thinks they may be at risk of having HIV should seek advice from their GP or local Genito-urinary clinic.

Dr Lorraine Doherty, a senior medical officer with the Department of Health, highlighted the importance of safe sex.

"This important report highlights the need for ongoing and sustained action to promote the 'safer sex' message, in particular amongst young people.

"Rates of chlamydia, syphilis and gonorrhoea continue to rise. If left untreated these infections can have serious health consequences such as ectopic pregnancy, infertility and, in pregnancy, miscarriage, stillbirth and congenital defects. Any person who believes they may be at risk or has symptoms suggestive of a sexually transmitted infection should consult their doctor or attend a Genito-urinary clinic."