The UK is towards the bottom of an international league for capital investment, according to a new survey.
The Trades Union Congress (TUC) said its analysis showed the Government needs to invest in "rail and roads, new homes and clean energy".
Currently, the UK is ranked the lowest out of 34 countries in the OECD (Organisation for Economic Co-operation and Development) - and is second lowest for information and communications technology equipment.
Their call for more investment was included in the TUC's submission to the Treasury ahead of next week's Autumn statement.
TUC general secretary Frances O'Grady said: "We can't just waltz into Brexit with our fingers crossed.
"If the Government doesn't invest in Britain it could go very badly wrong. And working people will pay the price with fewer jobs, lower wages and higher prices.
"But if the government invests in Britain, we can build an economy strong enough to thrive.
"We need investment in rail and roads, new homes and clean energy and in skills, education and fair pay for a world-class workforce.
"It's the right thing to do for better jobs and higher wages, and it's the best way to build an economy strong enough to compete in the global marketplace."