About 1,300 Pakistanis have been returned from Oman after being jailed for illegally entering the country.
The men say they were mistreated
Reports say they had paid up to $800 to people trafficking groups who promised them well-paid jobs in the Middle East.
One deportee said police in Oman beat the prisoners and denied them food. There has been no comment from Oman.
The group say they were arrested after travelling through Iran en route for Dubai. Pakistan has pledged to curb people smuggling.
However, the BBC's Idries Bakhtiar in Karachi says no really effective measures have been put in place.
Analysts say there is little incentive to check the trade which, it is alleged, is run by influential figures.
The deportees were brought back to Karachi by the Ansar Burmey charitable organisation, which works to repatriate Pakistanis stranded abroad.
Thousands of Pakistanis have been repatriated this year, while a large number are said to be still in prison in Oman.