The announcements come as Britain prepares for a budget on November 17, 2022 in which the government will lay out spending cuts and tax rises.
Russian President Vladimir Putin's regime would hear the chorus of global opposition to its actions, Sunak said.
"Russia's actions put all of us at risk," he said at the summit in Bali, Indonesia. "As we give the Ukrainian people the support they need, we are also harnessing the breadth and depth of UK expertise to protect ourselves and our allies."
Sunak also announced a 4.2 billion pound (US$4.94 billion) contract to BAE Systems to build five ships for the Royal Navy, a government statement said.
This contract, in addition to the three ships already under construction, comes as the next phase in the Type 26 frigate program and all the eight of the Type 26 frigates are expected to be completed by the mid-2030s, the statement said.
The British government has planned to build a total of eight Type 26s since 2015, when it cut the program from 13 ships.
Ships of the class will be advanced warships to be used in anti-submarine warfare to protect the British nuclear deterrent at sea, according to the government.
The prime minister and fellow leaders would stress at this week's meeting that Russia's role in the international system would never be normalized while the war in Ukraine continued, the statement added.
Sunak arrived at the summit in Bali, Indonesia, on Monday for a meeting that Russian Foreign Minister Sergei Lavrov will also attend.
In support to Ukraine, Britain said last week it would soon complete delivery of 1,000 additional surface-to-air missiles to the Ukraine's armed forces. Britain also announced delivery of a further 12,000 sleeping kits for extreme cold weather.
