Government departments will be obliged to connect to the G-Cloud, according to the head of the software as a service (Saas) initiative.
Chris Chant told the Business Cloud Summit in London that he estimated 60 percent of government decision-makers were not sure whether to take up the initiative, and 20 percent were "ready to go".
"There's still 20 percent that aren't interested, however," he said. "We know some will have to be dragged kicking and screaming, and they probably will."
Chant said the government was so keen to use cloud computing because of the "economics and agility" on offer.
"But we know it requires deep cultural change," he said. "Often people don't understand the exit costs from their gigantic contracts - commercial, technology and business de-integration."
He insisted that work would be on offer in all sizes of contract, adding that bidding processes would be affordable for small and medium-sized suppliers.
Pricing would be "clear and transparent" for government departments, he said.