The curfew will see 2.5 million people quarantined from Friday, as part of the government's bid to "get to zero" new cases of the virus.
However, Christians will be allowed to leave their homes to attend Palm Sunday services, after the Government gave in to public pressure.
Twelve months after the World Health Organisation first announced the start of the deadly outbreak, ebola has infected nearly 25,000 people in three West African countries, of whom 10,300 have died. With nearly 12,000 cases, Sierra Leone is the worst-affected, according to the charity.
Although the infection rate in Sierra Leone is falling, experts say case numbers continue to fluctuate on a daily basis.
Christian Aid's Sierra Leone Country Manager Jeanne Kamara, based in Freetown, said: "The emergency has continued longer than we had ever imagined. It's not over yet, so complacency must not set in. That's why the Government of Sierra Leone last week extended the state of emergency by 90 days.
"Worryingly there are signs of complacency, as people start to return to old ways and former behaviours. For instance, we've seen instances of people going against the local 'Ebola bye-laws'. These regulations are designed to reduce the risk of transmission.
Christian Aid has urged the Government of Sierra Leone to continue to emphasise the need for infection prevention and control measures within health facilities.
