The Fabian Society is calling for Chancellor Rishi Sunak to permanently extend the top-ups – which were introduced last Spring – or risk hitting "family finances in every corner of the country".
The think-tank's analysis of the latest figures show there were 25,635 households in Buckinghamshire receiving Universal Credit in November last year, and around 6,200 claiming Working Tax Credit in December.
This means a potential 31,835 households in the area would see their finances hit by the scrapping of the £20 uplifts – almost half (15,142) of which have children.
Both benefits were temporarily increased for one year – worth £1,000 per claimant over this time – as the coronavirus pandemic took hold in April last year.
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The weekly top-up is set to end after March 31, but it is hoped the Chancellor will announce a change of plan at the Budget on March 3.
Almost 6 million households could be affected across Great Britain, with around 654,000 in the South East, if not.
Reports suggest the benefits increase might be extended for a further six months, but the Fabian Society is calling for it to be made permanent for "the sake of communities across the whole of Britain".
Andrew Harrop, general secretary of the organisation, said: “These devastating figures show how the chancellor’s planned cut to Universal Credit and Working Tax Credit will hit family finances in every corner of the country.
“Removing £1,000 per year from so many households will reduce how much people can spend and suck millions of pounds out of local economies.
“Postponing the cut by another six months just kicks the can down the road, probably to a time when local unemployment will be even higher than today."
The think tank estimates the end of the benefit increases would take £6 billion out of household finances across Britain.
In Buckinghamshire, £32.5 million in social security income would be lost.
Department for Work and Pensions figures show more than a third of claims lodged since Universal Credit began have been made during the coronavirus pandemic.
There were 4.5 million claims for the benefit between March 13 last year and January 14 this year – 39% of the 11.4 million claims made since it was introduced in April 2013.
Jamie Grier, director of external affairs at anti-poverty charity Turn2us, said: “The Government did the right thing by introducing the uplift in the first place, and they must now do the right thing by making it permanent and extending it across our social security system.
"Otherwise, be in no doubt, poverty will rise, and the economic recovery will be slower.”
Minister for welfare delivery Will Quince said Universal Credit continues to support millions of people "during their time of need".
He added: “It is a vital safety net that has stood up to the challenge of the pandemic, and with thousands of new work coaches we are helping claimants across the country get back on their feet with one-to-one tailored support."