Ties not 'damaged'
Asked by British broadcasters whether he regretted damaging relations with Pakistan, Cameron said: "I do not accept that they have been damaged ... I look forward to discussing these and other issues (with Zardari)."
Despite the ISI's cancellation of the planned UK trip, Islamabad appeared to be playing down the row, with a government spokesman saying that Asif Ali Zardari, the Pakistani president, will still visit Britain next week.
Qamar Zaman Kaira, the information minister who was in Britain before Cameron's remarks, said the prime minister's comments were "contrary to the facts" and "not in good taste".
"But our reasonable reaction is ... we will discuss this matter at the highest level of the leadership and give them the facts," he told a news conference in London.
"If we go back into history, our relations with the UK are very good. And we want to keep up those relations, strengthen those relations."
Pakistan's help is crucial for US and Western efforts in stabilising neighbouring Afghanistan.
Cameron's remarks came days after classified US military reports published on WikiLeaks, a whistleblower website, revealed the ISI had aided the Taliban even as Pakistan's government was taking billions of dollars in US aid.
Hillary Clinton, the US secretary of state, said on her recent visit to Pakistan that she believed al-Qaeda leaders were still hiding in Pakistan and that some elements in the Pakistani government knew where they were.
Pakistan has in the recent past launched a large military offensive against al-Qaeda and Taliban fighters in its northwestern provinces bordering Afghanistan.
The ISI spokesman said more than 2,500 Pakistani soldiers had been killed and more than 4,000 wounded in battles against the fighters since the US-led war on Afghanistan in 2001.
More than 30,000 civilians have been killed or wounded in the same period, in addition to over 100 ISI officials, the spokesman added.
Pakistan's economic losses have been estimated by the government at more than $68bn since the US-led invasion of Afghanistan and the toppling of the Taliban government in 2001.