The UN Office on Drugs and Crime (UNODC) said at least 2.5 million migrants were smuggled during the course of 2016.
UNODC, in the first ever Global Study on Smuggling of Migrants, said migrant smuggling occurred in all parts of the world, generated an income of up to $7 billion.
The UN agency that fights drugs and crime, said the amount was equivalent to what the U.S. or the European Union spent on humanitarian aid in 2016.
"This transnational crime preys on the most vulnerable of the vulnerable," said Jean-Luc Lemahieu, UNODC Director of Policy Analysis and Public Affairs.
"It's a global crime that requires global action, including improved regional and international cooperation and national criminal justice responses," Lemahieu added.
The study described 30 major smuggling routes worldwide and found that demand for smuggling services was particularly high among refugees who, for lack of other means, might need to use people-smugglers to reach a safe destination fleeing their countries of origin.
Data suggested that many smuggling routes included unaccompanied or separated children, who might be particularly vulnerable to deception and abuse by smugglers and others.
According to the International Organisation for Migration (IOM), smuggling results in thousands of deaths each year from drowning, whereas others perish due to accidents or extreme terrain and weather conditions.
The Mediterranean appears to be the deadliest route, statistically, accounting for around 50 per cent of the total number of deaths.
Not only have some migrants been murdered along smuggling routes, they are also vulnerable to a range of other crimes, including violence, rape, kidnapping and trafficking in persons.
Turning to the gender composition, the study found that smuggled migrants were often influenced by the conditions they faced at home, however, most on the move are relatively young men, in parts of South-East Asia, a large proportion were women.
According to the report, smuggling networks often engage in systematic corruption ranging from the local to the international level, and operate a range of schemes, including fake marriages or employment rackets, counterfeiting travel documents and the corruption of senior officials.
Smugglers often advertise their business in diaspora communities, refugee camps or through various social networks online, involving migrant groups, UNODC said.
"Smaller-scale smugglers are either ethnically linked to their operating territories, or share ethnic or linguistic ties with the migrants they smuggle
"Some successfully smuggled migrants, then become smugglers themselves," the study found.