The move comes after warnings from the sector that the original deadline would put many charities at risk of breaching the law.
Under the act, commercial fundraising agents collecting on behalf of charities will have to state how much they will be paid for the appeal and explain which organisations will benefit. The provision was due to come into force on 1 January next year (Third Sector Online, 9 November).
A spokesman for the OTS said that a number of representatives from the sector, including lawyers and the Institute of Fundraising, had raised concerns that the six-week deadline was too short to allow charities to change the wording of their contracts with professional fundraising agencies.
"This is not something we should be criticised about," he said. "We have been talking and listening to people; that's why we are changing our timetable."
Benjamin James, senior associate at law firm Bircham Dyson Bell, one of the lawyers who raised the issue, said the OTS could not have foreseen the problem.
"I don't think that particular issue had been mentioned specifically before now," said James. "But the OTS was brilliant. It immediately looked into the problem and managed to turn it around in a week."
He added that the OTS had set the original date for the implementation of the statement as 1 January - two months later than the rest of the order - after recognising that charities would not be able to update their Christmas fundraising material in time.