The head of the police Mohammed Adamu announced that SWAT would carry out the duties which were done by the Special Anti Robbery Squad (SARS).
But many are using the hashtag #EndSWAT on Twitter to oppose the new unit.
They see the changes as not enough to reform the police.
Thousands of Nigerians have been protesting against the frequent cases of illegal detentions, assaults and shootings by SARS officers.
The mostly peaceful demonstrations have however been disrupted by police. Amnesty International said on Tuesday that 10 people were killed in the protests but other reports give a lower figure.
Some of Nigeria's biggest music stars, including Davido and Falz, have thrown their weight behind the demonstrators, who have been galvanising support on Twitter under the #EndSARS hashtag.
On Tuesday, they marched in the oil hub of Port Harcourt in defiance of a ban on demonstrations imposed by the state governor.
Protests were also held in the commercial hub, Lagos, the country's capital, Abuja, and four other cities.
What did the police chief say?
In a statement on Tuesday, Mr Adamu said all SARS staff will undergo a psychological and medical examination before further training and redeployment.
The new Special Weapons and Tactics (SWAT) team will fill the gaps left from the dissolution of SARS, he said.
The police chief also ordered the release of all detained protesters after a meeting with the National Human Rights Commission.
He did not say how many of them were in detention.
Mr Adamu added that Nigerians had the right to protest peacefully and ordered officers to stop using force against them. He acknowledged that the protesters' concerns were genuine and said they would be addressed by the government.
Protesters accuse the police of torture and extra-judicial killings.
The meeting also agreed that an independent panel would be set up to investigate allegations of abuse against SARS, and other police units.
On Monday, Mr Buhari promised that the disbandment of SARS was only the first step towards "extensive" reforms within the police force.
What are people saying?
On Twitter, where the protests have been organised, many people are using the hashtag #EndSWAT to remind others about their goal of reforming the police.