"All schools are ordered closed following further directives from the ministry of education," President Ellen Johnson Sirleaf said in a televised address to the nation.
"All markets at border areas are hereby ordered closed until further notice."
Liberia, along with neighbouring Guinea and Sierra Leone, is struggling to contain an epidemic that has infected some 1,200 people and left at least 670 dead across the region since the start of the year.
"Friday August 1 is declared a non-working day and is to be used for the disinfection of all public facilities."
She said Liberia, where the death toll stands at 129 from 249 cases, would be contributing $5.0 million (3.7 million euros) as an "initial contribution" to the regional fight against Ebola.