David Cameron, the Prime Minister, has said the lobbying act will not affect the majority of charities and campaigning organisations.
Cameron was responding to a letter from Sir Stephen Bubb, head of the chief executives body Acevo, which was sent to the leaders of the three main political parties earlier this month. The letter urged them to repeal part 2 of the act, which many charities believe will significantly impede their campaigning activities.
In his reply, Cameron said he was sorry to read of Bubb’s concerns but could not agree with the sentiment of his letter, which said the act was "an injustice perpetrated by government".
Cameron said it was up to the Electoral Commission to produce guidance in the coming months to help charities and other non-party organisations comply with the legislation.
"I hope you will agree that it is vital that information about the act is not misleading," Cameron wrote. "Indeed, as you will be aware, the legislation will not affect the majority of charities and other campaigning organisations."
He said that the act would apply only to charities that spend money to procure the electoral success of a particular party or candidate, and the registration threshold of £20,000 would exempt most groups.
In his letter, Cameron said he stood by his commitment to review the legislation after the general election in 2015. "I am sure there will be a chance for you to represent your members’ views about the impact of the legislation as part of this," he said.
The Transparency of Lobbying, Non-party Campaigning and Trade Union Administration Act 2014 gained royal assent in January, despite voluntary sector concerns that the legislation would significantly affect their ability to campaign on issues that could be regarded as party political in the run-up to elections.
In response to the letter, Bubb said in a statement: "It is important that his views on a piece of legislation that has such huge implications for freedom of speech and democracy are heard loud and clear.
"Charities and campaigners will note his promise that the lobbying act won’t restrict the crucial role that we play in speaking out for the vulnerable and voiceless. Acevo will be watching closely.
"We will hold the Prime Minister to his other promise of a review in 2015. Acevo will continue to work tirelessly with charities and regulatory bodies to ensure that the voice of civil society is not silenced by government."