Sections 2, 3 and 4 of the Quarantine Act (CAP Q2 LFN 2004) conferred such powers on President Buhari.
After intense pressure from the Nigerian public especially from senior legal practitioners and other prominent citizens, President Muhammadu Buhari on Monday announced the signing into law of the COVID-19 Regulations.
Sections 2, 3 and 4 of the Quarantine Act (CAP Q2 LFN 2004) conferred such powers on President Buhari.
It was the legal framework needed to enforce the lockdown order in Lagos, Ogun and the FCT issued by Buhari on Sunday during a nationwide broadcast.
The announcement was made on Monday night by Special Adviser to President Buhari on Media and Publicity, Femi Adesina.
President Buhari had addressed Nigerians on the outbreak and continued spread of Coronavirus 35 days after the country's first case was recorded.
A flurry of criticisms over his silence and perceived lack of concern on the damage caused by the pandemic had pushed him to speak.
Recall that earlier on Monday, Senior Advocate of Nigeria, Femi Falana, had said that the lockdown order could not be enforced except it was backed by a law.
He said, "No doubt, the President is empowered to adopt any measure deemed fit to combat the dangerous disease but such measure have to be spelt out in a Regulation made pursuant to section 305 of the constitution or under the Quarantine Act.
"Otherwise the presidential order on restriction of movement in the affected areas cannot be enforced by the police."
Another lawyer, Inibehe Effiong, while reiterating Falana's position, in fact vowed to challenge the illegality of Buhari’s action in court.
He said, "After a deep reflection on President Muhammadu Buhari's decision to lock down all movements in Lagos, Ogun and Abuja by presidential fiat for 14 days, I have resolved to challenge this unconstitutional action in court.
"No responsible, democratic and civilised country will throw its constitution and laws into the dustbin in an effort to tackle a pandemic like COVID-19 the way President Buhari has done. Freedom of movement is a fundamental right guaranteed by Section 41 of the constitution.
"While it is conceded that this right is not absolute, Section 45 of the constitution is clear to the effect that freedom of movement can only be taken away in the manner allowed by a law that is reasonably justifiable in a democratic society. Buhari has not relied on any law.
"If Buhari is convinced that extraordinary measures are needed to contain Coronavirus, the proper action would have been for him to issue an instrument published in the official gazette of the government and make a proclamation of a state of emergency in Lagos, Ogun and Abuja."
Also adding his voice to the issue earlier on Monday, Nobel Laureate, Prof Wole Soyinka, said that President Buhari had no constitutional backing to declare a total lockdown of Lagos, Ogun and Abuja.
He said, "The worst development I can conceive is to have a situation where rational measures for the containment of the Corona pandemic are rejected on account of their questionable genesis.
"So, before this becomes a habit, a question: does President Buhari have the powers to close down state borders? We want clear answers. We are not in a war emergency.
"We need to exercise collective vigilance, and not compromise the future by submitting to interventions that are not backed by law and constitution."
However, earlier defending Buhari’s declaration of a lockdown in all three cities, Nigeria's Attorney-General of the Federation, Abubakar Malami, said that the President did not need any special legal framework to have the order enforced as the Quarantine Act already covered that.
Malami said, “The correct position remains that the President acted rightfully under the powers conferred on him by the Quarantine Act 1990 CAP 384 LFN.
"Section 3 of the Act enables the President to declare any part of Nigeria as an infected area. Section 4 of the Act further empowers the President to make regulations to prevent the introduction, spread and transmission of any dangerous infectious disease."
But with Buhari’s latest move on Monday, Malami now stands alone on the matter.
Enforcement of the order is now expected to commence in Lagos and FCT while it will take effect in Ogun from April 3.