LONDON (Reuters) - A simple see and treat approach using a test costing $2 could help doctors prevent 100,000 cervical cancer deaths a year in women in poorer countries, British scientists said on Friday.

Cervical cancer is the leading cause of cancer death among women in developing nations where the main barriers to tackling the disease are poor health service infrastructure and high costs of screening and vaccines.

But British researchers said visual inspection with acetic acid (VIA) -- which costs significantly less than $9 human papillomavirus (HPV) or cervical cell lab tests more commonly used in developed nations -- could be the answer.

Around 300,000 women worldwide die from cervical cancer each year and up to 85 percent of those deaths occur in developing countries.

VIA is an effective and affordable tool to screen women for pre-cancerous lesions of the cervix in under-resourced countries, said David McGregor of University College London, who led the research.

Coupled with simple treatment measures, VIA could potentially reduce these cancer deaths by a third, which means nearly 100,000 women saved each year.

VIA is a simple test where a very small dose of acetate acid solution is applied to the cervix to detect pre-cancerous lesions. A positive result can be treated immediately.

This is referred to as the see and treat approach and experts say it can work well in small clinics without advanced equipment and laboratories.

Drug firms Merck & Co and GlaxoSmithKline make Gardasil and Cervarix vaccines which protect against a number of strains of HPV -- the most common sexually transmitted disease in the world and the main cause of cervical cancer.

But unlike in developed nations, where cervical screening programs are well established and vaccination programs against HPV are growing, access to tests and vaccines in many countries in Africa, Asia and southern America is limited.

The study in the Obstetrician & Gynecologist journal said research in rural and isolated communities had shown that VIA is accurate, acceptable to women, and cuts cancer death rates.

But it said raising awareness about screening programs to ensure higher uptake in the population was also a challenge.

(Reporting by Kate Kelland; Editing by Louise Ireland)