Rishi Sunak is set to reshuffle his Cabinet with the appointment of a new Conservative Party chairman and the possibility of reforms to Whitehall departments.

The Prime Minister is expected to announce a replacement for Nadhim Zahawi, who was sacked as party chairman and minister without portfolio for breaking the Ministerial Code over his tax affairs.

Mr Sunak is also reported to be considering breaking up Grant Shapps’ Department for Business, Energy and Industrial Strategy (Beis).

During his Tory leadership campaign in the summer of 2022, Mr Sunak said he would create a standalone energy department.

The potential overhaul could be “relatively limited”, with a “domino” effect caused by the naming of a successor for Mr Zahawi, The Times reported, citing a Government source.

The Sun reported that Beis and the Department for International Trade could be merged, and a new science and digital department created, leaving culture and sport as a separate unit.

A reconfiguration would also affect the composition of the Cabinet, raising questions over the future of Mr Shapps and International Trade Secretary Kemi Badenoch.

Dominic Raab is expected to survive a potential reshuffle this week, as Mr Sunak has indicated he will wait for the outcome of an inquiry into the Deputy Prime Minister’s conduct before taking any action.

Mr Raab, who is also the Justice Secretary, is being investigated by senior lawyer Adam Tolley KC over bullying allegations – with dozens of officials thought to be involved in eight formal complaints. Mr Raab has denied the bullying allegations.

The Cabinet-level changes are expected to be completed ahead of a meeting of Mr Sunak’s top team, which has been delayed until Tuesday afternoon to allow for the reshuffle process.

Cabinet ministers thought to be under consideration to succeed Mr Zahawi include Mr Shapps, Commons leader Penny Mordaunt and trade minister Greg Hands.

Development minister Andrew Mitchell, another of the names suggested as party chairman, told Times Radio: “I’m certainly not expecting to be called upon to do that.

“But one should always try to do what the Prime Minister wants you to do.”

Treasury minister Andrew Griffiths would not be drawn on the prospect of breaking up the business department.

“If the Prime Minister has got something to say on how to reorganise government then we’ll have to wait and see that,” he told BBC Radio 4’s Today programme.

Asked if it was a mistake to disband the Department of Energy and Climate Change in 2016, he said he joined government from a business background.

“To me, it is all about outcomes, it is not about process. Obviously if there are ways of streamlining the way this Government can deliver on the people’s priorities, then that’s important.”