A study by the TUC also found that manufacturing will slump into "steep decline", hitting jobs as well as pay.
TUC general secretary Frances O'Grady will set out the negative impact Brexit will have on wages, jobs and rights at work when she launches the union organisation's latest drive to persuade people to vote to remain in the EU.
The TUC said its research found that by 2030 the average weekly wage in Britain would be £38 lower outside the EU.
The manufacturing sector would be hit seven times harder than services because it exports so much to the EU, said the report.
Jobs in manufacturing tend to be higher-skilled, better paid and more secure than in the services sector, so Brexit would worsen the quality of work in the UK, it was argued.
Ms O'Grady said: "To date, the debate about our membership of the EU has been dominated by business. But today I want to change the tone and set out why working people should vote to Remain.
"At a time of continuing hardship, Brexit would be a disaster for working people - for our wages, for our jobs and for our rights.
"£38 a week may not be much for politicians like Boris Johnson, but for millions of workers, it's the difference between heating or eating, between struggling or saving, and between getting by or getting on."
Mick Cash, general secretary of the Rail, Maritime and Transport union, said: "If Europe is a workers' paradise then why are whole parts of France and Belgium shut down today by strikes against attacks on pay and conditions and why are half of young people in parts of Southern Europe without work?
"It is crucial that all sides are represented in this debate including those trade unionists who see Europe as a drag weight on jobs, pay and public ownership."
Vote Leave chairwoman Gisela Stuart said workers would be better off if the UK votes to leave.
She said: "The EU has been a disaster for workers, with unemployment in the double digits across the eurozone and harsh austerity measures implemented at the expense of vital public services.
"The head of the In campaign Lord Rose has himself said that workers will get a pay rise if we Vote Leave. And as the Bank of England has confirmed, uncontrolled immigration has played a key role in bringing down wages.
"After we Vote Leave, we can take back control of immigration and spend the £50 million we send to the EU every day on our priorities."