Labour leader Ed Miliband is set to warn Chancellor George Osborne not to tighten the "squeeze" on ordinary families when he delivers his autumn statement.
Mr Miliband, who is visiting south London, will say that families are already facing a "quiet crisis" in living standards as a direct result of the Government's current policies.
"The squeeze on living standards has since become an everyday reality under this government," he is expected to say.
"This quiet crisis is a cost of living crisis for hard-working people who feel squeezed every which way at the moment. Prices are rising in shops. People feel fearful about their jobs."
He will urge the Chancellor not to pay for the Government's new youth jobs programme by freezing in-work tax credits for low income families, as some reports have suggested that he is planning.
"What a symbol that would be of the wrong choices this government is making. Finally waking up to the problem of youth unemployment and paying for it by hitting the lowest-paid working families," he is expected to say.