The cell, adjacent to the Jaitu police station, was in shambles for decades and was visited by Congress leader Rahul Gandhi in 2008.
A portion of the cell collapsed on Wednesday, Senior Superintendent of Police Rajbachan Singh Sandhu said.
Nehru, who became India's first Prime Minister in 1947, was lodged when he along with freedom fighters K. Santhanam and A.T. Gidwani reached Jaitu on September 21, 1923, to take part in a 'morcha' against the Britishers under the Gurdwara reforms movement.
They were detained for violating prohibitory orders.
As per the archives, Nehru was kept in the cell briefly before being sent to the Nabha jail, which too is currently in shambles.
In his autobiography 'Discovery of India', Nehru had mentioned his arrest at Jaitu.
Santhanam too had mentioned their arrest and had written before his death in 1980 that he was handcuffed with Jawaharlal Nehru with a single chain at Jaitu in 1923.
In February last year, then Punjab Tourism Minister Navjot Singh Sidhu during his visit to Faridkot had announced to undertake a Rs 50 lakh project for the facelift and preservation of the prison cell. But nothing had happened since then.
Even the previous Congress-led UPA government at the Centre had sanctioned Rs 65 lakh for its maintenance, but no major renovation work was carried out, locals said.
( With inputs from IANS )