OTTAWA -- A key witness in the trial of suspended Senator Mike Duffy has postponed his appearance because of serious health problems.

Gerald Donohue was hospitalized last week and might not be able to appear until next week, the court learned.

Donohue is an important figure because of his role in collecting and dispersing about $65,000 in Senate funds through a contract with Duffy.

Duffy faces 31 charges of fraud, bribery and breach of trust, with several of them related to payments made through the Donohue master contract.

Some of those sub-payments were reviewed in court Tuesday -- one to speechwriter and journalist L. Ian MacDonald, and a series of others to an Ottawa-area photo processing store.

Defence attorney Donald Bayne says Donohue is a decent man, and that he has been portrayed poorly in the context of the trial.