Peers have warned of a "constitutionally inappropriate shift of power" from Parliament to Government.
Laws are being drafted with vague wording that allows ministers significant discretion about how they are implemented, according to a House of Lords committee.
Extensive use of secondary legislation is allowing the Government to dodge proper scrutiny and avoid parliamentary defeat, it also said.
The Children and Social Work Bill, which will shake up adoption rules and aims to improve social care standards, paves the way for ministers to introduce criminal offences that have not been defined in the proposed new law, according to the constitution committee.
Peers said they were "concerned not only at the extent of the delegated powers put forward by Government, but at the effect this had on the effectiveness of parliamentary scrutiny of primary legislation and on the balance of power between Parliament and the executive as a whole".
Committee chairman Lord Lang of Monkton said: "The Children and Social Work Bill continues a worrying trend in which Parliament is asked to agree legislation that is lacking crucial details that allow it properly to scrutinise Government proposals.
"Our political system relies on Parliament having the ability to scrutinise legislation through the full multi-stage process in both Houses.
"The Government's reliance on legislating by regulation undermines that and risks poorly constructed proposals becoming law.
"The Children and Social Work Bill proposes giving the Secretary of State significant powers to establish a new social work regulator, to define its functions and powers, and to create new, and currently undefined, criminal offences.
"Changes of that nature should be set out to at least some degree in primary legislation so they can be debated, scrutinised and improved.
"Instead, by giving the minister the power to make these changes by regulation there is a risk Parliament will again be denied its proper role in holding the Government to account."