Visitors would have paid a 3,000-pound cash bond before arrival in the UK - which would be forfeited if they failed to make the return trip.
"We have no limit on the number of students who can come," he said.
He also said he encourages a visa service for business as he wants to see the ties between the two countries grow.
Cameron, who will make a day-long visit before heading to Sri Lanka to attend Commonwealth Heads of Government Meeting (CHOGM) on November 15-16, will hold talks with Prime Minister Manmohan Singh on key bilateral and regional issues.
