However, Prime Minister Boris Johnson is pushing ahead with ambitions he outlined in the Conservative manifesto which are due to span the next three years. Mr Sunak is arguing government departments should only be allotted cash for one year, analysts are saying.
The chancellor may allow for some exceptions such as for the construction of hospitals and the recruitment of police officers.
It is also understood the government’s HS2 rail project could be granted more than one year’s funding.
Still, Mr Sunak’s concerns could lead to a change of plans regarding military developments, among other things.
Spending plans are due to be announced in November after the government’s integrated review.
Tobias Ellwood, Chair of the House of Commons Defence Select Committee, has criticised any delay to military commitments.
He said on Twitter yesterday: “The integrated review is critical in defining our ability and desire to help share the world as a force for good.
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He said, according to The Times: “Normally it makes sense to give Whitehall departments the certainty of a three or even four-year settlement but not this time.
“We don’t know where the economy will be in a year’s time.”
The Treasury said the spending review is due to finish in “the coming weeks”.
Meanwhile, Mr Sunak was also recently warned against raising taxes on the self-employed in a bid to raise more cash for the Government.
Derek Cribb, head of the Association of Independent Professionals and the Self-Employed (IPSE), claimed “one in three” self-employed people had not been given any government support, adding the idea of making them pay an extra tax “is a little challenging as a sell”.
Conservative MPs have hit out at such plans before, including in 2017 when then-Chancellor Philip Hammond had to backtrack on plans to increase National Insurance payments by self-employed people.
Former Lib Dem leader Vince Cable has also hit out at Mr Sunak in recent times, accusing him of “an untimely and ungenerous tightening of the purse strings”.
He said in an op-ed for the Independent: “Sunak’s rapid transition from spendthrift to Scrooge has not yet been noticed by the admiring public.
“Nor has it yet got to the more gullible Tories, who have persuaded themselves that this wunderkind is a fusion of Franklin Roosevelt and Margaret Thatcher, who will rescue them from the backlash against Bumbling Boris.”
The Chancellor was recently urged to plug tax loopholes after online sales giant Amazon managed to avoid paying a new digital services tax.