The Charity Commission wants to delay the introduction of new rules banning people with convictions for certain offences from acting as charity staff or trustees, which are due to come into force in April.
The rules, which would automatically disqualify people with convictions for sexual and terrorism offences, bribery or disobeying commission orders from being trustees or managers of charities, were introduced as part of the Charities (Protection and Social Investment) Act 2016.
The act was passed in March, but the government said it would not apply the automatic disqualification rules until April 2017 to give affected charities and people time to prepare or apply for a waiver.
But the commission has now said it wants the introduction pushed back until at least September 2017 to give charities more time to deal with the impact of the new rules.
A commission spokesman said: "These changes will have significant impact on some individuals and we have always been clear that charities and affected individuals must have enough time to prepare for these changes properly.
"In order to do so fully, we are working with the Office for Civil Society to set a commencement date later in 2017.
"We consider that this should not before September and are hopeful that this will be agreed."
A spokeswoman for the Department for Culture, Media and Sport, which houses the OCS, said the changes to the automatic disqualification regime would take effect in 2017, but did not specify when or whether the OCS would agree to the commission’s request.
She said: "We will provide advance notice of these changes so that the small number of people affected have time to properly prepare."
The existing rules automatically bar only those people with convictions involving deception and dishonesty. The commission spokesman said this had been "considered generally to be too narrow" and did not cover several areas that it was widely accepted should merit disqualification.
Charities that work with offenders are the most likely to be among those affected and have expressed concern about the widening of the rules, saying it could damage trustee diversity and prevent people whose criminal convictions were irrelevant to their current roles from contributing to the sector.
The commission spokesman said: "We continue to work with a number of umbrella bodies and rehabilitation charities as we further develop these plans to ensure that charities, trustees and senior staff members have all the relevant information and enough time to take the appropriate steps."