Labour's plan to raise the living wage to £10 an hour would give a quarter of British workers a pay rise, new analysis by the party claims.
It said around 40% of workers would benefit from Labour's plan in some parts of the country, with warnings the Tories had not done enough to boost pay.
The Government said 1.7 million workers had benefited from the latest rise in the living wage in April.
Shadow business secretary Rebecca Long-Bailey said "bold and imaginative measures" were needed to tackle low pay.
"The stagnation of real wages currently being experienced is unprecedented since at least the Second World War," she added.
"People should be rewarded for a full day's work and need the dignity that comes with decent wages."
New regional analysis by the party shows that 41% of workers in Weymouth and Portland, as well as West Somerset, would get a pay rise under Labour's proposals.
In Birmingham, more 100,000 people would get a pay rise.
Labour has highlighted forecasts from the Office for Budget Responsibility (OBR) which say the national living wage will be £8.75 per hour in 2020, not £9 per hour as had initially been promised.
The OBR also predicts the minimum wage for 21 to 24 year olds will only be £7.75 per hour by 2020.
Labour said it would extend its living wage to all workers aged 18 or over.
Party leader Jeremy Corbyn has previously suggested the policy would also apply to 16 and 17 year olds.
A spokesman for the Department for Business, Energy and Industrial Strategy said: "Around 1.7 million workers have benefited from a pay rise of up to £600 a year following the latest rise in the national living wage in April.
"Low paid workers will continue to see their pay go up, with the rate set to increase to 60% of median earnings by 2020."
The living wage increased by 4.2% in April, from £7.20 to £7.50.
Mr Corbyn will be in Glasgow on Thursday to outline plans to tackle poverty and inequality alongside Scottish Labour leader Kezia Dugdale.