"Although I have not been associated with the programme for the past 10 years, I know that it has been running without any break and the process of uranium enrichment is in progress," Khan said in an interview with the Dawn newspaper.
"Though the concerned departments are not giving "final shape to new nuclear weapons", the materials are being prepared and could be assembled at any time if required," he said.
Asked if the nuclear programme was running satisfactorily, Khan said it was "running well".
Reports have suggested that Pakistan's nuclear weapons programme is expanding at a rapid pace and the country is expected to have a fourth operational reactor by 2013 to ramp up production of plutonium.
US congressional official working on nuclear issues have said that intelligence estimates suggest Pakistan has already developed enough fissile material to produce over 100 warheads and manufacture between eight and 20 weapons a year.
Asked about safety of Pakistan's nuclear assets, Khan said the Taliban or any external force could not seize them because of a "highly secured system which has been improved gradually".
The nuclear assets were safe from day one and no country should be worried about them, he claimed.