Islamist terror group Boko Haram's insurgency in Nigeria's northeastern regions is forcing thousands to flee their homes and into the neighbouring countries of Cameroon, Chad and Niger, according to local authorities.

While the number of Nigerians crossing to Chad and Niger is increasing, the border towns of Cameroon are witnessing the largest influx of people displaced by Boko Haram's violence.

"We've been flooded here in Mora [in Cameroon] by Cameroonians and Nigerians fleeing Boko Haram," a police officer in the town, speaking on condition of anonymity, said.

"The day before yesterday, there were already more than 10,000 people in Mora. Not a day goes by without more people coming."

The officer added that over 6,000 people had arrived in the town of Kolofata from the Nigerian border states.

The United Nations Office for the Coordination of Humanitarian Affairs (UNOCHA) said last month that Boko Haram's violent attacks on villages in the northeastern states of Borno, Yobe and Adamawa had forced approximately 650,000 people from their homes.

Nigeria's National Emergency Management Agency said that almost 11,500 people have fled the Nigerian town of Gwoza, which was seized by the militants last month.

Following its capture of the town, the terror group announced a new 'Islamic State' where it implemented Sharia law, beheading Christian men in the area and forcing their wives into marriage with the group's members, according to local media reports.

The unnamed Cameroonian police officer confirmed that, after the arrival of thousands, registration of the displaced Nigerians had been initiated in Mora.

"People are everywhere: in schools, under trees and in the markets," he added. "They're all coming from [Cameroonian and Nigerian] villages in the Kerawa area."

Amid reports that Nigerian troops have also fled Boko Haram into the border towns of Cameroon, Andrew Noakes, coordinator of the Nigerian Security Network (NSN), said that President Goodluck Jonathan's administration must do more to equip forces in the embattled region.

"Morale is extremely low because often troops are sent into battle with inadequate equipment and insufficient ammunition. There is an urgent need to ensure the army is properly equipped," he said.

Earlier this year, the group - who wish to expand their 'Caliphate' in northeastern Nigeria - kidnapped more than 200 schoolgirls in the village of Chibok, bringing global attention to the west African nation's fight against terrorism.

According to Human Rights Watch, the militants have killed at least 2,053 people since the beginning of 2014.