Angela Rayner sparked confusion this morning by suggesting that Labour would reverse the Government's cut to income tax, before party sources rowed back on the comment.
The Chancellor Kwasi Kwarteng claimed on Twitter that Labour would deliver a "tax hike for millions".
In yesterday's mini-Budget, Mr Kwarteng brought forward a 1p cut to the basic rate of income tax by one year to 2023, as well as announcing the additional rate of 45 per cent would be scrapped altogether.
Appearing on the BBC's Today programme, Ms Rayner was asked whether Labour would reverse the income tax cut.
She replied: "Well, we've said that, you know, the income tax cut is the wrong priority. So, yes, we don't think that that's the priority.
"We will set out our tax proposals which will guarantee that those on the lowest wages their cost of living will improve, we will have sustainable growth into the future. We will invest in high-skilled jobs and renewables, so we're self-reliant on our energy needs.
"We'll set out our proposals towards the next election, but we've been very clear that those with the broadest shoulders should pay more."
Mr Kwarteng seized on the comment, tweeting: "A Labour tax hike for millions."
However, after the interview Labour sources said that the deputy leader was criticising the Chancellor's decision to scrap the additional rate - which Labour would reverse - but that the 19 per cent basic rate would remain if the party gets into government.
During the interview, Ms Rayner argued that the UK's tax rates were "reasonably low anyway, especially around business tax", and that the mini-Budget was "a very dangerous gamble on our economy".
Appearing on BBC Breakfast, Chris Philp, the Chief Secretary to the Treasury, defended abolishing the additional rate, saying that in cost it accounted for "1/20th of the measures announced yesterday".
"To get Britain growing we need to reduce the burden of taxation," he said.
"We're not into the politics of envy where we want to deliberately penalise people who have been working hard."
Mr Philp was also asked about a tweet he sent yesterday morning in which he said it was "great to see sterling strengthening on the back of the new UK Growth Plan", before the pound fell to a fresh 37-year-low against the dollar.
He said: "Looking at the markets clearly the dollar has been quite strong against a number of currencies in the last few months."
He added: "What I was mostly saying on Twitter yesterday was how important this growth plan is to increase wages, to create new high pay jobs, encourage investment, get Britain moving and produce the tax revenue to fund public services… and British business agrees."