British Prime Minister Rishi Sunak arrived Monday on the Indonesian island of Bali for the G20 leaders' summit, the first time since Russia invaded Ukraine.
He would condemn Russia's "barbarism" in Ukraine at the talks, urge a deal with Moscow allowing safe passage of grain shipments from its neighbour to be extended and call for "a G20-wide commitment never to weaponise food production and distribution", Downing Street said in a statement.
"The Prime Minister will use the G20 as an opportunity to call out (President Vladimir) Putin's barbarism and force Russia to confront the global suffering caused by this senseless campaign of violence," it said.
The new British leader will hold a series of bilateral meetings with allies including US President Joe Biden, Japanese Prime Minister Fumio Kishida and Australia's Anthony Albanese.
Britain's first-ever premier of Indian descent will also meet with Indian Prime Minister Narendra Modi.
In an opinion piece for Britain's Daily Telegraph newspaper published Sunday evening, Sunak slammed Putin for not attending the summit and said Britain would "not let our economic future be held hostage by the actions of a rogue state".
"Leaders take responsibility. They show up. Yet, at the G20 summit, in Indonesia this week, one seat will remain vacant. The man who is responsible for so much bloodshed in Ukraine and economic strife around the world will not be there to face his peers," he wrote.
"He won't even attempt to explain his actions. Instead, he will stay at home and the rest of us will get on with the task at hand."
Sunak is due to return to Britain early on Thursday and head straight into his finance minister's presentation of an emergency budget statement.
The statement is expected to include painful tax hikes and spending cuts, after Sunak's short-lived predecessor Liz Truss panicked markets with a spree of unfunded tax cuts.