The builder and contractors responsible for the Reigners Bible Church in Nigeria that collapsed at an episcopal consecraton, killing and injuring dozens of people, are to face a police investigation.

Udom Emmanuel, governor of Akway Ibom state, in southern Nigeria has ordered the arrest of the building contractor according to the state news agency.

Senate President Bukola Saraki has also demanded an investigation.

The Reigners Bible Church was still under construction and Emmanuel was at the service in the church when the roof collapsed on top of everyone there as the church's founder, Apostle Akan, was being consecrated.

Emmanuel and Akan both survived unscathed.

Emmanuel tweeted that he "shared in the agony of the moment".

He also declared Sunday and Monday to be "national days of mourning". He described the "deep sorrow" felt by the entire country at the tragedy.

Reports of the number of fatalities ranged from 27 to 160. Dozens more were injured.

One of the survivors, Eno Etim, on Sunday, said the building collapsed shortly after a lady was called to lead the praise worship.

Etim said there was no sign of disaster before the actual collapse.

Another survivor was interviewed from hospital by local media. He said the roof collapsed about half an hour into the service. "Suddenly, the roof from the middle fell on worshippers. The governor was quickly rescued. But others were not that lucky."

Building collapses are tragically common in Nigeria.

Building regulations are often breached and materials sometimes fail to conform to industry standards.

In 2014, there was international outrage when 116 people were killed after a six-storey church building collapsed. Nigerian preacher, "Prophet" TB Joshua, was indicted for criminal negligence.

After this latest disaster Nigerian Government tweeted: