Both AMs and the assembly government can bid for new laws
MPs are calling for a cut in the number of bids by the Welsh Assembly Government and AMs for more powers.
The Welsh affairs select committee say 11 proposed legislative competence orders (LCOs) risk swamping the system, when they expected only four or five.
The assembly's limited powers for more laws, under review by Welsh Secretary Paul Murphy, must win the MPs' backing.
The assembly government said MPs do have an important role to play, and they will examine their views closely.
The MPs have told Mr Murphy they are concerned there should be a smaller number of high quality bids, saying too many bids could bring the process into disrepute.
Mr Murphy said the process of scrutinising the proposed Welsh-only laws needed "practical commonsense being applied to it" as both MPs and AMs found their way through the process.
He told BBC Radio Wales: "I think the fact that it is so very new that it's meant that we've had to see how we can deal with it.
"That's why I decided a month or two ago that I would look at the scrutiny arrangements. We'll keep that under review over the next year as well."
PROGRESS OF PROPOSED LAWS
Vulnerable children: awaiting royal approval
Domiciliary care: has royal approval
Additional learning needs: has royal approval
Environmental protection: not had Whitehall clearance
Affordable housing: in committee in Parliament and assembly
Mental health services: awaiting Whitehall clearance
Domestic fire safety: not yet introduced to Parliament
Welsh language: at the drafting stage
Carers: at the drafting stage
Bus and coach services: at the drafting stage
National flags on registration plates: AMs to debate in October
Mr Murphy said he was impressed with the way MPs and AMs had dealt with the complexity of some of the proposed legislation.
He said he expected "about four" LCOs to be ready by October, with the process for scrutinising them speeding up later.
He added: "Some are more difficult and complex and sometimes more controversial than others and therefore require more debate and more scrutiny."
Officials in Cardiff and London had been issued with guidance notes on handling LCOs, he said.
Welsh affairs select committee chairman Hywel Francis said better planning was needed between Cardiff Bay and Westminster, but he was confident that the workload would be reduced by the autumn.
He said: "My committee has been working incredibly hard and catching up very quickly. Our workload has increased by 50%. We're not complaining about that."
Mike German, leader of the Welsh Liberal Democrats, said the MPs were trying to "narrow" the powers to the assembly by asking for the purpose of the proposed laws.
He said: "They should not be asking what are we going to to do with them when we've got them.
"That is a very worrying issue in relation to those powers coming to Wales."
Earlier this month, assembly Presiding Officer Dafydd Elis-Thomas said it was for Parliament to keep up with the assembly.
He said the system dealing with LCOs would become simpler over time.