Labour and Tory MPs have criticised the Government's lobbying reforms as an attack on free speech which would gag charities from voicing their concerns.
The backbench MPs said the legislation failed to properly monitor large lobbying firms while putting unnecessary restraints on the charities and think-tanks which might want to speak out about Government policies.
Commons Leader Andrew Lansley sought to play down the concerns, telling MPs that charities and other voluntary organisations should not be "alarmed".
He said the legislation was "perfectly rational" but added the Government would amend the Bill if there was any chance it could prevent MPs going about their usual work.
As part of the Transparency of Lobbying, Non-Party Campaigning and Trade Union Administration Bill, a cap of £390,000 would be set on the amount any organisation - excluding political parties - could spend across the UK in the run-up to elections.