Coastal communities have been “blighted” by “nine years of vicious austerity and Tory cuts”, Jeremy Corbyn has said in a speech.
Speaking in Hastings, East Sussex, the Labour leader also pledged to end the “evil of in-work poverty”.
But the Conservatives say seaside areas can benefit from a £3.6bn fund.
BBC analysis this week found that workers living in costal parts of Britain earn £1,600 less on average per year than those living inland.
The research also found that two-thirds of coastal areas had seen a real-terms fall in wages since 2010.
The constituency of Hastings and Rye was held by Amber Rudd for the Conservatives by just 346 votes at the last general election, but she has since quit the party and sits in the House of Commons as an independent.
Labour is hoping to win the seat, which Ms Rudd will not contest again, at the next election.
In his speech, Mr Corbyn said poverty and inequality were “not inevitable”.
“In the fifth-richest country in the world, no-one should be forced to rely on a food bank to feed their family, no-one should be sleeping rough on our streets, and nobody should be working for poverty wages,” he said.
Citing parliamentary research, he said one in five adults in Hastings and Rye could be in receipt of universal credit when it is fully rolled out.
Universal credit is the benefit for working-age people, replacing six benefits – including income support and housing benefit – and merging them into one payment:
Food banks in Hastings and Rye say they distributed nearly 90,000 meals last year.
Mr Corbyn has said a Labour government would immediately increase the minimum wage to £10 an hour and build one million affordable homes over 10 years.
He also trumpeted plans, unveiled at the party’s conference, for a future Labour government to invest in new offshore wind farms and use the profits generated from energy sold to improve recreational and leisure facilities in struggling areas.
Defending the government’s record, Minister for Local Growth Jack Berry said: “Thanks to a thriving economy and record employment, the government can afford to invest more in communities across the country – something that would be put at risk with a reckless high-tax, high-debt Corbyn government.”