Sierra Leone's 72-hour nationwide shutdown has entered its final day, as criticism grew that the extreme action aimed at containing the spread of the deadly Ebola virus was no more than a publicity stunt.

Most of the west African country's six million people have been confined to their homes since midnight on Friday, with only essential workers such as health professionals and security forces exempt.

Almost 30,000 volunteers are going door-to-door to educate locals and hand out soap, in an exercise expected to lead to scores more patients and bodies being discovered in homes.

But independent observers have voiced concerns over the quality of advice being given out, deeming the shutdown a "mixed success" in the Western Area, the region that includes the capital Freetown.

"While the supervisors were well trained, the visiting teams to families in some parts in the Western Area had poor training and could not deliver the information properly," said Abubakarr Kamara, from the Health for All Coalition, a local charity.

"From my observation, many of them were too young to be involved in the exercise and in one or two households where I witnessed their intervention, there were hardly messages given to the families which were beneficial to the households."

Ebola fever can fell its victims within days, causing severe muscle pain, vomiting, diarrhoea and - in some cases - unstoppable internal and external bleeding.

The outbreak has killed more than 2,600 people in Guinea, Liberia and Sierra Leone this year, cutting a swathe through entire villages at the epicentre and prompting warnings over possible economic catastrophe from the World Bank.

The widespread fallout from the outbreak was underlined by India's decision on Saturday to postpone plans for a summit in New Delhi to be attended by representatives of more than 50 African nations.

The spread of the virus made it "logistically difficult given the public health guidelines to manage" the Third India-Africa Forum Summit, said a foreign ministry official.

Joe Amon, health and human rights director at New York-based advocacy organisation Human Rights Watch, described the shutdown as "more of a publicity stunt than a health intervention".

"Publicity - or really crisis communication - is what is urgently needed in this epidemic, but it should focus on spreading information and building trust with the government. The shutdown is the wrong approach," he told AFP.