Re-examining Brexit could "throw up a huge dust cloud of uncertainty" for companies, warned a former adviser to Andy Burnham.
Top economist Andy Haldane told Radio 4's Today Programme he thinks the UK might secure a better arrangement with the EU.
He asked: "Could we strike a somewhat better deal on both the trade front and freedom of movement front?"
"Yes, we could, and yes, we probably should," he replied.
"Is that a reason to open up the whole debate about Brexit, rerun that fractured, fractious debate?" he continued.
Haldane argued that such a move would be damaging for growth, saying it would "throw up a huge dust cloud of uncertainty".
He added that businesses, which can hardly afford more instability in the current climate, would be especially affected.
The former Bank of England chief economist has criticised the prime minister ahead of the Budget, which aims to target banks and mitigate damage to public finances.
Haldane noted that the uncertainty surrounding Brexit before and after the 2016 vote acted as a major drag on investment and growth.
PM Andy Burnham has signalled openness to re-joining the EU after the next election, but has pledged to keep the UK out of the Single Market and Customs Union during the present parliamentary term.
