SYDNEY (Reuters) - Australian Defence Minister Linda Reynolds will take a period of medical leave following advice from her cardiologist over a pre-existing medical condition, her office said on Wednesday, hours before she was scheduled to deliver a speech to journalists.


"As a precautionary measure, Minister Reynolds has this morning been admitted to a Canberra hospital," the defence minister's office said in a statement.


Reynolds was scheduled to deliver a speech to the National Press Club later in the day and was expected to face questions related to the allegation of rape made by one of her former staff.


"Linda was desperate to appear before the National Press Club today, desperate to appear and it was only on the strongest medical advice that she took the reluctant decision not to do it," Health Minister Greg Hunt told reporters in Canberra.


Brittany Higgins, who worked as a media adviser to Reynolds when she was Defence Industry Minister, last week said she was raped by a colleague in Australia's parliament two years ago.


Higgins had said she felt pressured not to proceed with a formal complaint for fear of losing her job. Reynolds last week apologised to Higgins but denied that she or her staff pressured her not to pursue a police complaint.


Prime Minister Scott Morrison also apologised to Higgins for the way her complaint was handled at that time, ordering a probe into the government's workplace culture.


Higgins is expected to make a formal complaint about the alleged rape on Wednesday, Australian media reported, allowing authorities to pursue an active investigation about the incident.


Foreign Affairs Minister Marise Payne will be the acting defence minister until Reynolds returns from leave, though her office did not specify for how long she will be away.