The NATO chief will be the first international leader Sunak has met in Downing Street since he took office last month.

Wednesday's talks will centre on UK support for Ukraine after Russia's invasion in February, and the alliance's future, Sunak's office said.

"As the war in Ukraine continues to rage, we must not take peace at home for granted," Sunak said in a statement.

"I am determined the UK will be the bedrock of NATO for generations to come," he added.

"But in order to face the challenges of the future we must evolve as an alliance to meet, and remain ahead of, the threat from our adversaries."

NATO said separately that Stoltenberg would also meet UK foreign minister James Cleverly.

Stoltenberg will meet Sunak after visiting a military facility where Ukrainian troops are being trained by British military.

Britain has offered to train a total of 19,000 Ukrainian recruits in vital battlefield skills including marksmanship, weapons handling, urban and trench warfare and first aid.

Sunak announced on Tuesday that the UK is sending Ukrainian soldiers extra equipment to help them get through the harsh winter, including more than 25,000 sets of extreme cold weather clothing, 12,000 sleeping kits and 150 heated tents.

One of the new prime minister's first calls in the job was to Ukraine President Volodymyr Zelensky, who had close ties with former prime minister Boris Johnson.

Sunak promised him he would continue Britain's "steadfast support" and solidarity for Ukraine.