Communications minister Peter Shanel Agovaka confirmed the decision to Solomon Times Online, saying public misuse of the platform was the main concern.
"Abusive languages against ministers, prime minister, character assassination, defamation of character - all these are issues of concerns," Agovaka said.
The country was lacking legislation on internet usage and cybercrime, which was particularly worrying when it came to what children were accessing and being exposed to, he said.
"The use of the internet now in Solomon Islands needs to be properly regulated to safeguard our young people from harmful content."
It was not an attack on freedom of expression, pointing out that freedom of the press was still protected, he said.
Agovaka also said the decision would not require Parliament's approval.
"The government is still in discussion with the operators to work out how this can be done. The operators shall need to establish a firewall to block Facebook."
However, Agovaka said the initial decision, made last week, did not take into consideration the economic impacts of the decision, which would be investigated fully before the ban was imposed.
There are only four countries in the world where Facebook is banned around the clock - they are China, Iran, Syria and North Korea.
However, North Korea's ban is indirect because it is a complete internet ban.
