The commission previously received an average of about 50 serious incident reports a week, which would cover issues including safeguarding, but also fraud or financial failure, among others.
In the wake of the safeguarding summit chaired on 5 March by Penny Mordaunt, the international development secretary, the commission reported that it had received 80 serious safeguarding incidents from 26 charities since the Oxfam scandal first emerged.
In response to questions from Third Sector today, the regulator said that in the first month since concerns about Oxfam and Haiti first emerged there was "roughly a doubling of serious incident reports".
It said: "This increase relates specifically to concerns about safeguarding (both current and historic).
"These reports cover a wide spectrum, from internal audits showing that safeguarding procedures were not followed in certain situations, right through to reports of allegations or actual incidents of abuse, including sexual abuse of staff, volunteers and beneficiaries, including children. Some reports relate to risks rather than specific incidents of abuse or harm."
The regulator said it was still seeing a higher than average level of serious incident reports, but it expected this would level off once charities had reported appropriate historic serious incidents.
It said the commission was assessing the reports to see whether the individual charities had responded appropriately and would be investigating further where this was not the case.
"We will also be undertaking proactive work to ensure prompt and full reporting of serious safeguarding incidents," it said.
"We have long said we believed there to have been under-reporting in the sector, and we hope that charities generally now better understand their responsibility to fully and frankly report all serious incidents to us."
The news comes after Sarah Atkinson, director of policy, planning and communication at the regulator, told a meeting of the All-Party Parliamentary Group on Charities and Volunteering yesterday that the volume of reports of safeguarding incidents by charities had "increased enormously" since the Oxfam story first broke on 9 February.
"Charities that were not reporting incidents are now doing so," she said, adding that charities that previously thought they had incidents under control were realising that they did not.
"We thought we had a problem bigger than we realised, and we do have a problem that is bigger than we realised," said Atkinson.
She urged charities to report incidents when they happened and not hope that they could be ignored, potentially leading to worse repercussions further down the line.
"You are trading your 24-hour reputation for the long-term reputation of the charity," she warned.
Atkinson said the regulator had an "enormous challenge" of capacity, in what could be considered a nod to the commission’s ongoing consideration of introducing charges on the largest charities in order to boost its budget, which has been nearly halved in real terms over the past decade.