"If an allegation is upheld then I would resign," Raab told the British broadcaster.
In January, at least 24 UK civil servants reportedly filed formal complaints against Raab.
In November, Raab received three complaints from his former employees accusing him of "creating a culture of fear" and bullying his subordinates. UK Prime Minister Rishi Sunak, in turn, approved Raab's request to investigate the matter, adding that this was "the right course of action."