UK leader Rishi Sunak apologised on Friday for leaving the D-Day anniversary commemorations in northern France early to conduct a television interview during Britain's general election campaign.

Opposition politicians accused Sunak of bringing "shame" to the office of prime minister by skipping a major international ceremony with other world leaders in Normandy on Thursday.

Sunak attended a British government event before returning home and missed the main ceremony at Omaha Beach, attended by France's President Emmanuel Macron and US President Joe Biden.

"After the conclusion of the British event in Normandy, I returned back to the UK," Sunak said in a post on the social media site X.

"On reflection, it was a mistake not to stay in France longer –- and I apologise."

Sunak was interviewed by ITV News in an interview that is not due to air until Wednesday.

Jonathan Ashworth, of the main opposition Labour Party, accused Sunak of prioritising "his own vanity TV appearances over our veterans".

Ed Davey, the leader of the smaller Liberal Democrats group said Sunak had "brought shame" to his office and "let down our country".

Beleaguered Conservative leader Sunak said in his post that the anniversary "should be about those who made the ultimate sacrifice for our country".

"The last thing I want is for the commemorations to be overshadowed by politics," he wrote.

"I care deeply about veterans and have been honoured to represent the UK at a number of events in Portsmouth and France over the past two days and to meet those who fought so bravely."

The D-Day ceremonies marked the 80th anniversary of the launch of Operation Overlord when tens of thousands of allied troops stormed the beaches of Normandy in northern France on June 6, 1944.

The vast military operation paved the way for liberation of occupied France and the end of the war against Nazi Germany.

Sunak, British leader since October 2022, is widely tipped by pollsters to lose the election on July 4, with Labour expected to return to power after 14 years in opposition.