A defiant Mr Sunak rebuffed calls from within his own party to exclude the country from the conference, to be held at the home of the UK’s Second World War codebreakers.
Mr Sunak insisted there could be “no serious strategy” developed to manage the risks posed by AI without the input of one of the world leaders in the technology.
But his predecessor Liz Truss slammed the move, saying she was “deeply disturbed” and called on the prime minister to cancel the invitation.
Ms Truss hit out at the Chinese state which she said had “used and abused technology to aid its oppression of millions and attacks on freedom and democracy”.
The former PM warned Beijing views AI as “a means of state control and a tool for national security”.
And she said that the concerns which led the current deputy prime minister Oliver Dowden to decide to strip Huawei of its role in the UK’s 5g network over the next few years “should have informed decisions about invitations to the Bletchley Park summit”.
She added that “no reasonable person expects China to abide by anything agreed at this kind of summit, given their cavalier attitude to international law”.
Both Ms Truss and another former Tory PM David Cameron rounded on Mr Sunak earlier this month after he used his party conference speech to scrap the second leg of the HS2 network to Manchester and announced plans to ban some young people from ever being able to buy cigarettes.
The row comes as Mr Sunak faces intense pressure over his attitude to China.
It comes as the White House revealed that US vice-president Kamala Harris will attend the UK summit at Bletchley Park.
In a major speech ahead of the gathering Mr Sunak warned of the serious risks posed by AI – including of terrorists using the technology to make bioweapons and even human extinction.
Defending his move to include China in talks, the PM said: “I know there are some who will say (China) should have been excluded but there can be no serious strategy for AI without at least trying to engage all of the world’s leading AI powers.”
Mr Sunak added: “That might not have been the easy thing to do but it was the right thing to do.” But he conceded that even though they had accepted the invitation: “I can't say with 100 per cent certainty that China will be there.”
While Chinese officials will take part in the first day of discussions on Thursday, they will not be invited to the second, which will involve like-minded countries. Mr Sunak will convene a small group of companies and experts, while science secretary Michelle Donelan will lead ministerial meetings on the second day.
Despite Mr Duncan Smith’s view that the decision to invite China was “astonishing” – arguing that “engaging with them only makes us look weak” – some China hawks welcomed the idea of Beijing officials being at Bletchley Park.
Senior Tory MP Bob Seeley, who has pushed for a tougher stance on Beijing, told The Independent: “It’s broadly good news that [Mr Sunak] has invited China.”
The foreign affairs select committee member said: “It poses a risk that China will see what everyone is up to, and then do their own thing. But you don’t want them to shut them out of the conversation before the conversation has started. There is always the hope that China will change.”
Mr Seeley added: “The worst case for society will be used by bad rulers to effectively analyse dissent before it happens and make opposition to dictatorial regimes impossible – just like George Orwell predicted. So there’s a risk China will abuse it.”
“There will be an open society approach, a closed society – and the battle will be for countries in the middle, like countries India, the Middle East and south America.”
Before the US vice president attends the summit, she will deliver a speech outlining her administration’s approach to AI next Wednesday, the day before the event kicks off.
Asked if the Biden administration could distract from the UK conference, Mr Sunak’s official spokesman. “It’s right that we work collaboratively with the US on this … that is entirely right.”
Earlier, Mr Sunak’s deputy Oliver Dowden had said that ministers would wait and see whether Chinese officials actually came to the UK for the meeting.
“It is the case that you wait and see who actually turns up at these events,” he said, although he added: “We do expect them to come.”
Since he took over at No 10 a year ago, Mr Sunak has adopted a softer approach to China than Ms Truss.
She had been preparing to label Beijing a “threat” to the UK before she was ousted from office. Mr Sunak has instead described China as an “epoch-defining challenge”.