Jardine Lloyd Thompson Group (JLT) has been blacklisted by an international union, which has accused the broker of conducting business in Burma.
The International Confederation of Free Trade Unions (ICFTU), which represents 156 million workers worldwide, warned JLT risked becoming an accomplice to forced labour.
It said it hoped its naming and shaming action would embarrass JLT into pulling out of the country.
Burma's military rulers have been accused of human rights abuses including forced labour and poor provision of health and education.
The UK government discourages trade, tourism and investment with Burma.
ICFTU deputy director of trade union rights Janek Kuczkiewicz said: "We wrote to JLT earlier this year saying we had evidence they were trading with Burma and we asked them to pull out [but] we've had no response."
He said the ICFTU had "identified a commercial link" between Jardine Lloyd Thompson and Burma but could not give further details.
He said: "There is a huge problem with forced labour in Burma which has been around for decades.
"Companies trading with or in Burma are supporting the junta which is responsible for forced labour.
"It's impossible to do business in Burma without directly or indirectly supporting the junta.
"If JLT remains in Burma, it is an accomplice to forced labour which is a crime against humanity.
"We would encourage shareholders to put pressure on the company to withdraw and if it refuses, to reconsider their investment in the company."
JLT was one of 250 companies on the blacklist published last week.
Despite requests, Jardine Lloyd Thompson was unable to comment before Insurance Times went to press.