Nearly 4,000 people with HIV/Aids have reported at treatment centres around Pakistan, government and World Health Organisation (WHO) officials say.
Only a small number of people with HIV come forward for help
The figure is a fraction of the total number of Pakistanis with the virus.
A UNAids report last year said that between 80,000 and 140,000 people were infected - and the rate could spiral because of under-reporting of cases.
The WHO has been funding a three-year, $4.5m anti-retroviral programme in Pakistan since late 2005.
The drugs for the programme are imported from India, and a number of doctors and nurses have been trained for the purpose in India and Italy.
An HIV-Aids newsletter of the Ministry of Health put the total number of reported cases at 3,933, but only about 618 of them were registered with nine treatment centres countrywide.
Pakistani officials say a low detection rate and stigma associated with the disease were hampering the treatment of HIV/Aids patients.
The problem is further compounded by a lack of awareness about the infection.
"People think it is exclusively caused by adultery, and are therefore reluctant to approach health services," says Quaid Saeed, WHO's national medical officer for HIV/Aids in Pakistan.
A joint study conducted recently by UNAids and the Aga Khan Univeristy in Karachi reported that 80% of known cases in Pakistan involved people who had been deported from the Gulf states for having Aids.
Lack of detection "may cause an Aids epidemic in Pakistan, especially among high-risk population sub-groups such as injecting drug users, sex workers and unsuspecting spouses," says Mr Saeed.
The WHO is trying to implement a plan under which prevention and treatment programmes would go hand in hand.
The treatment centres offer not only treatment, but also counselling sessions for patients and relatives.
"Unfortunately, prevention programmes take time to produce results and high risk sexual behaviour is not easily changed into safer practices," Mr Saeed says.
But of late there has been evidence that some sufferers are breaking their silence.
"An increasing number of patients are approaching us because they know they can receive specialist treatment which can prolong their lives," says Dr Yasin Malik, who is in charge of an anti-retroviral treatment centre in the north-western city of Peshawar.
Aids was detected in Pakistan in 1987 and has been spreading since.
The scale of the country's problem is dwarfed, however, by that in neighbouring India, which has more people living with HIV than any other country in the world.
According to UNAids, 5.7 million people had been infected there by the end of 2005.