The resignation marks the first political crisis facing Liberia's new president Joseph Boakai since his inauguration at the end of January.

Boakai "has received and accepted a letter of resignation from the recently confirmed Minister of National Defence Mr. Prince C. Johnson," the presidency said in a statement.

The president swiftly announced a provisional replacement, naming General Geraldine Janet George to the key post.

In his resignation letter, Johnson cited "the current political and civil disturbances occasioned by the protest of women believed to be wives of service men".

He wished to "preserve the peace and security of the State", the statement added.

Wives of Liberian soldiers set up roadblocks near the capital Monrovia and elsewhere in the country, forcing Boakai to cancel planned National Army Day celebrations on Monday, an AFP correspondent reported.

The women were airing multiple grievances ranging from low salaries and pensions, to a lack of social security, electricity shortages and corruption within the armed forces.

They also demanded the defence minister's resignation, blaming him for a reduction in the salaries of Liberian soldiers returning from peace missions in Mali.

The first roadblock was assembled on Sunday on the outskirts of Monrovia near the Edward Binyah Kesselly barracks on the road leading to the international airport.

New roadblocks made of kitchen utensils and makeshift supplies appeared elsewhere in the country on Monday.

Drivers stuck in long traffic jams on the road leading to the airport opted to abandon their vehicles and continue their journey on foot.

President Boakai asked the army on Monday to ensure that the roadblocks were lifted "immediately", according to the presidency.

He met with soldiers' wives on Sunday and vowed to carefully examine their concerns and set up a commission, his team said.

He ordered the restoration of electricity to the Edward Binyah Kesselly barracks and free classes in the school located within the compound.

"The President has been in office for 20 days only and he has taken immediate steps already to address some of these issues which have been festering for more than five years," his team said in a statement.

Boakai "advised everyone to remain calm and peaceful as the government seeks to address their concerns", it added.