Around 50 reforms have been introduced. All will take effect within four years, with the majority coming into play in 2009.
Among the changes is a move to get single parents on income support to actively seek work once their youngest child reaches a certain age.
Initially this will be 12 or older, from October 2008, but the age falls in subsequent years to 10 or older from October 2009, and seven or older from October 2010.
Work and pensions secretary Peter Hain said: “We have made huge progress over the last decade - 600,000 children lifted out of poverty. But a new vision is needed to achieve our goal of full employment in our generation.”