Officials said one prisoner, who had recently undergone surgery, was unfit to travel and could not join the others as they set off by road for Lahore after being freed from Malir Jail in the port city on Wednesday morning.
The fishermen were freed a day after a mix-up over the release of Sarabjit Singh, an Indian who has been on death row for two decades following his conviction for alleged involvement in a string of bombings in Punjab province.
Hours after reports emerged that Pakistan was to free Sarabjit, the presidential spokesman clarified that steps were being taken to release another Indian prisoner Surjeet Singh, whose death sentence was commuted in 1989 and who has already served a life term.
Officials said the Indian fishermen would be repatriated via the Wagah land border on Thursday after the completion of certain formalities.
Reports suggested that Surjeet Singh, currently held at Kot Lakhpat Jail in Lahore, was expected to be freed along with the fishermen but there was no official word in this regard.
Talking to reporters in Islamabad, Rehman Malik, the head of the interior ministry, said Pakistan is taking steps to free Indian fishermen arrested for straying across the maritime boundary without conducting any trial.
Officials said about 130 Indian fishermen are still in Malir jail in Karachi.
Pakistan and India arrest scores of fishermen every year on charges of violating territorial waters. "By releasing the fishermen, Pakistan intended on maintaining friendlier ties with India. We hope India will soon release Pakistani fishermen as well," said Sindh Minister for Law and Prisons Ayaz Soomro.
The two countries have released scores of prisoners, a majority of them fishermen, since they resumed their peace process last year after a gap of over two years in the wake of the 2008 Mumbai terror attacks.
The two sides are working on an arrangement for the speedy repatriation of fishermen detained for inadvertently crossing the maritime boundary.
