Forced evictions in Nigeria's largest city Lagos have cost around 9,000 people their homes or livelihoods, Amnesty International and a local rights group said Monday.

Tens of thousands more could be at risk if the government proceeds with plans to redevelop the slum area of Badia East, said Amnesty's report, issued jointly with the Social and Economic Rights Action Centre (SERAC).

"It is estimated that close to 9,000 residents of Badia East lost their homes or livelihoods," said a statement on the report.

"If these plans proceed as described, tens of thousands will be at risk of forced eviction and face possible destitution."

Residents said armed police and bulldozers swooped without warning in February, forcing them from their properties, in what the government has termed the first phase of its clearance plan.

"We want the state government to remember that we are not animals," Tunde Aworetam, a pastor in the affected community said at a press conference in Lagos.

He and other witnesses said police physically abused some residents as they were ejected from their homes.

"The effects of February's forced eviction have been devastating for the Badia East community where dozens are still sleeping out in the open or under a nearby bridge exposed to rain, mosquitos and at risk of physical attack," said Oluwatosin Popoola, Amnesty International's Nigeria researcher.

The report calls on Lagos authorities to halt the forced evictions, aimed at bringing order to the chaotic and crowded metropolis of 15 million people.

Slums have sprung up throughout Lagos as Nigerians pour into the sprawling city in search of work.

But those evicted from Badia East claimed to have been living on the land in question since 1973.

Amnesty and SERAC said the land is owned by Nigeria's federal government, but Felix Morka, executive director at SERAC, dismissed suggestions that people squatting on land they do not own could be forcibly removed without warning.

"You do not need a certificate of ownership" in order to have basic rights, Morka said, adding that in Nigeria "it's easy to declare anyone a squatter" given the unclear rules and bureaucracy surrounding land titles.

He added that the Lagos state government led by Governor Babatunde Fashola had breached numerous domestic and international laws by authorising the evictions, having failed to secure a court order or provide any relocation assistance.

The governor said he was committed to improving living conditions in Lagos in a speech broadcast on a private Nigerian television station Monday, adding that his aim was to build a community instead of preserving a slum.

"Instead of bulldozing you, we will bulldoze your difficult conditions," he said.

Amnesty and SERAC used before and after satellite images showing concrete houses and other structures razed to the ground to dispute claims by an official that the area cleared was a rubbish dump.

A survey carried out by residents estimated that at least 266 buildings containing homes and businesses were completely destroyed, affecting an estimated 2,237 households.

Similar evictions have taken place across Nigeria, with thousands of residents left homeless.