Coming at the G7 meeting in Hiroshima, the new package includes a ban on importing Russian diamonds, and Russian-origin copper, aluminium and nickel.
Leaders of the club of rich democracies said their aim was to cut Kremlin revenues and "starve Russia of G7 technology, industrial equipment and services that support its war machine".
They said a price cap on Russian oil agreed at last year's summit in Germany "is working" to cut Moscow's income from energy exports.
"Our support for Ukraine will not waver. We will not tire in our commitment to mitigate the impact of Russia’s illegal actions on the rest of the world," they said in a joint statement.
Ukrainian President Volodymyr Zelenskyy is expected to attend the G7 summit in Japan in person, officials said on Friday.
Mr Putin's invasion of Ukraine 15 months ago has prompted waves of sanctions that have helped plunge his country into recession and drained the Kremlin's war chest.
The G7 wants to tighten the screws further, strengthening existing sanctions, closing loopholes, and subjecting more Russian companies and their international partners to punitive restrictions.
The UK said it was also targeting imports of aluminium, copper and nickel.
“As today's sanctions announcements demonstrate, the G7 remains unified in the face of the threat from Russia and steadfast in our support for Ukraine,” said Prime Minister Rishi Sunak.
The G7 is likely to stop short of an outright ban on Russian diamonds, at least for now.
But according to officials, the summit will signal a determination to act.
“Russian diamonds are not forever,” said EU Council President Charles Michel. “We will restrict trade.”
Talks between G7 allies, including the US and French presidents, Joe Biden and Emmanuel Macron, will centre on military and economic support for Ukraine to show a united front.
The UK is also preparing sanctions against 86 people and organisations connected to Russia’s energy, metals, defence, transport, and financial sectors to apply further pressure on Mr Putin and his supporters.
Downing Street expects other G7 allies, which also include Germany, Italy and Canada, and the EU, to impose similar sanctions.
The diamond export industry was worth more than $3.7 billion to Russia in 2021, but Downing Street conceded that direct imports had been low since the UK placed sanctions on state-owned miner Alrosa last year.
Mr Sunak’s spokesman said discussions would include future security guarantees and long-term deterrence to prevent Ukraine ever facing a similar situation.
On the Chinese threat to Taiwan, the official said: “Guarding against economic coercion is something that the Prime Minister is pushing for.”
As the first British prime minister to visit Hiroshima, Mr Sunak signed a pact with Mr Kishida to bolster the Indo-Pacific region amid concerns over Chinese aggression.
“For the sake of global peace and security, we must show that brutal violence and coercion does not reap rewards,” he said.
“As today’s sanctions announcements demonstrate, the G7 remains unified in the face of the threat from Russia and steadfast in our support for Ukraine.”
On Sunday, Mr Sunak will meet Indian Prime Minister Narendra Modi, who is attending the summit as a guest.
Mr Modi has remained neutral on the Russian invasion, calling for peaceful dialogue to end the war.
Mr Sunak told reporters travelling with him in Japan that he has seen “positive” steps from India in its stance.