Oxfam says there is an "invisible army" of exploited workers in Britain
Up to two million workers in Britain are at risk of exploitation because of their vulnerable work status, a report by the TUC has suggested.
Its research found some employees being paid £1 an hour, some working 70 hours a week and others facing sexual abuse.
The union body, which set up a commission to uncover the extent of such poor treatment, described the situation as a "national scandal".
The government said it was boosting penalties for rogue employers.
The TUC, which set up the Commission on Vulnerable Employment last year, said exploitative employment practices seen in the 19th Century were still being used by some employers today.
It found home-workers being paid £1 an hour, fast food employees working 70 hours a week and domestic staff facing physical and sexual abuse.
Kate Wareing, director for UK Poverty for the charity Oxfam, said there was an "invisible army" of exploited workers in the UK, who were doing some of the “lowest paid, most insecure and unpopular jobs in the country".
The report called for a campaign to raise people's awareness of workers' rights, extra funding for bodies such as the Heath and Safety Executive and the setting up of a special Fair Employment Commission to police rogue employers and enforce workers rights.
Commission member Kevin Beeston, chairman of public service management company Serco, said it was "time society stopped turning a blind eye to these workplace abuses".
TUC general secretary Brendan Barber said the treatment uncovered by the commission was a "national scandal" and said urgent action was needed.
"Good employers have nothing to fear - and much to gain - from policies that stop them being undercut by bad employers who break the law or use loopholes to get round it," he added.
As part of the commission's report, a Community union survey of 8,000 workers also found three out of four workplaces used temporary and agency workers, with some on contracts of a week or under. Some were on just two hours' notice.
General secretary Michael Leahy said this was "clear exploitation" of agency workers, who, he said, were being used to undermine the pay and conditions of permanent staff.
Employment relations minister Pat McFadden said the TUC's report would be looked at as part of the government's vulnerable workers' forum, which is due to report back in the summer.
But he said the exploitation of such workers was "unacceptable" and the government had worked hard to bring in extra employment rights such as the national minimum wage, paid holidays, health and safety regulations, statutory maternity and paternity leave and sick pay.
"Most employers do the right thing, but some are doing the wrong thing, so it's vital we enforce the law," he said.
"That's why we're boosting penalties and enforcement to catch those who don't pay the national minimum wage and doubling the amount of agency inspectors to investigate abuses."
New regulations also ensured bosses could not unfairly deduct accommodation and other expenses from people's wages, he added.