Stephen Bubb, head of chief executives body Acevo, said Hope was doing a good job and that The Daily Telegraph's revelations did not reflect on his ability. "As yet there has been no suggestion of a breach of the rules," he said.
The umbrella group NCVO declined to comment, as did Tory charities spokesman Greg Clark. Debra Allcock Tyler, chief executive of the Directory of Social Change, said she was confident Hope had done nothing wrong.
She added that it was disappointing for Hope to be involved in the "cash for kids" story because the sector was about access for the excluded. "People with disabilities, mental health issues, educational deficits, all those who might benefit hugely from the chance to work for an MP, are effectively being excluded by essentially nepotistic practices," she said.
Hope said he had done nothing wrong. A statement read: "Both my son and daughter have worked in my office on both a paid and voluntary basis. They never worked for me when they should have been studying."
His son was employed while a student, and his daughter between school and university.
A spokeswoman for Hope said he had employed 10 people on temporary contracts and no one who requested work experience had been turned down.