Director General of Police (Jails) Alexander Jacob said both men and women inmates were smuggling phones inside their private parts.
"Even in the most high security prison in the world in Pennsylvania, there have been instances where mobile phones are smuggled inside the prison," Jacob said.
"In our country's high security jails in Hyderabad and in Delhi's Tihar jail, this has happened," he said.
The jail department has drawn flak after three inmates posted their pictures on social media this week.
The three inmates are the prime accused in the murder of former Communist Party of India (Marxist) leader T.P. Chandrasekheran last year.
The top police official said that during the previous Left government, at least 135 mobile phones were seized from various jails in the state.
"There are 52 jails in the state, and since the present government assumed office in 2011, 68 mobiles have been seized, which includes 28 from Kannur jail alone," he said.
When an inmate was asked to remove his clothes and searched in Kannur jail, the police department came under criticism, he said.
The inmate stripped himself and stood naked facing the road.
"This became news and a few jail officials were suspended," the jail official added.
Jacob, however, said it needed to be proved that the inmates actually posted their pictures on social media from jail.
"Unless scientifically proved that the post was done from jail and the so-called mobile phone calls were made from the jail, it would be difficult for me to believe it. At present, scientific investigations are going on," Jacob said.
Jails in Kerala are currently overcrowded. There are 7,600 prisoners in the 52 jails in the state, whose total sanctioned strength is 6,000.
"The jail department is heavily understaffed and one-third of the total 1,298 vacancies in jails are lying vacant."
"The jail staff also comes under attack from the inmates and with a skeletal staff, it's very difficult to maintain discipline," Jacob said.
"One reason we have been able to maintain discipline is we give skill training to the inmates and as a result, they are all earning and are gainfully employed," he added.
--IANS (Posted on 05-12-2013)