Rachel Reeves has been urged by a think tank to cut national insurance and increase income tax to create a "level playing field" and protect workers' pay.
The Resolution Foundation said the chancellor should send a "decisive signal" that she will make "tough decisions" on tax.
Ms Reeves is expected to outline significant tax rises in the upcoming budget in November.
The Resolution Foundation has suggested these changes should include a 2p cut to national insurance as well as a 2p rise in income tax, which Adam Corlett, its principal economist, said "should form part of wider efforts to level the playing field on tax".
The think tank, which used to be headed by Torsten Bell, a Labour MP who is now a key aide to Ms Reeves and a pensions minister, said the move would help to address "un