The country's government has said Christians will be able to leave to attend church on Palm Sunday.
According to a 2009 estimate 71.3% of the population is Muslim with just 26.8% being Christian.
It is a year since the outbreak of Ebola was declared in the worst-affected countries of Guinea, Liberia and Sierra Leone.
The virus has killed more than 10,000 people in the last 12 months.
There had been a drop in cases in Sierra Leone but the number has increased recently prompting President Koroma to order six million people to stay indoors from 6am on March 27 to 6pm on the 29th.
But he has said Christians can break the curfew early on the 29th to go to Palm Sunday church services.
It is a change in the government's position after Christians were forced to cancel events in the lead up to Christmas because of curfews.
It comes as health experts say the Ebola outbreak is far from coming to an end.
The charity Medecins Sans Frontieres claims governments in the region didn not share enough information when it first started.
It has also criticised the initial slow response of the World Health Organisation.