Rumours that the Labour leader will begin a “revenge reshuffle” of his shadow cabinet in the new year have drowned out the party’s attacks on the Conservative government, the shadow culture secretary Michael Dugher has said, in a jibe at Jeremy Corbyn’s aides.

Unsourced briefings to several newspapers over Christmas, attributed to people in Corbyn’s camp, claimed that members of the shadow cabinet – including Dugher, as well as the shadow foreign secretary, Hilary Benn, and the shadow defence secretary, Maria Eagle – could be removed as revenge for siding with the government over the question of whether to extend airstrikes against Isis to Syria.

Likening Corbyn to a Jedi from Star Wars, Dugher wrote in the New Statesman that “the idea that Jeremy Corbyn is a person motivated by ‘revenge’ is something that I don’t recognise for a single second”, adding: “Revenge is not very Jedi. It’s also not very new politics.”

It is understood that Corbyn wants the party to speak with one voice on matters relating to defence and military intervention and it is felt among his allies that splits over foreign policy have overshadowed the shadow cabinet’s unity over economic and domestic matters.

“As someone who used to have his Christmases ruined dealing with political journalists, I know how difficult it is attempting to manage the media during the holidays, so I also have a little sympathy with Jeremy Corbyn’s press handlers,” said Dugher, who served as shadow transport secretary in the last parliament.

“The festive season is also the silly season. Mischievous hacks bombard aides with relentless and leading questions in the hunt for a new line to keep an old, bad story for Labour running.”

But Dugher argued that predictions of a “revenge reshuffle” from sources close to the Labour leader served “to drown out our attacks on the Conservative government, or ... overshadow announcements about the positive things Labour would do differently in government”.

The Labour deputy leader, Tom Watson, seen as a link between the leader’s office and the parliamentary party, told the Guardian on Tuesday he knew nothing about a reshuffle.

“I have not been made aware that a reshuffle is due,” he said. “What I have seen is that there has been much speculation over Christmas.

“Any reshuffle is for the leader of the Labour party. It is a very lonely job. I’m sure that if there is going to be one he will let me know. Leaders have to pick the team they want and I will make my views clear.”

Speaking on BBC Radio 4’s Today programme on Tuesday, the shadow chancellor, John McDonnell, insisted: “The future Labour administration will be determined by the leader of the Labour party.”

He refused to say whether Benn would keep his job in any future reshuffle, instead saying that the shadow foreign secretary had “an important part to play” in the Labour party.