Former federal MP Craig Thomson submitted an expense claim to the Health Services Union with the name of an escort agency's parent company handwritten on the document, a court has been told.
Thomson, 49, is facing dozens of dishonesty charges over his alleged misuse of union-issued credit cards on escorts and other personal expenses while national secretary of the HSU and a Labor MP.
Former HSU bookkeeper Belinda Ord told Melbourne Magistrates Court that Thomson would often use memoranda, rather than receipts, to justify his credit card expenses.
Once such memorandum, tendered as evidence on Tuesday, shows Thomson claimed $770 as a business expense for a "dinner function" in May 2005.
The memorandum features the handwritten words "Internat Immobiliare".
The court has previously been told International Immobiliare is the trading name of Sydney escort agency Boardroom Escorts.
A handwriting expert is expected to give evidence at the hearing.
Ms Ord said Thomson had told her to write guidelines on credit card usage after another staff member had signed up to an astrology service.
Ms Ord's predecessor, Nurten Ungun, said Thomson had instructed staff that union-issued credit cards were only for work-related expenses.
Ms Ungun said Thomson had once reprimanded her for using a credit card on flights and accommodation for a personal trip.
Ms Ungun said she repaid the money to the union before resigning the following day.
Thomson has pleaded not guilty to 145 charges of obtaining financial advantage by deception over the alleged misuse of $28,449.
The hearing continues on Wednesday before Magistrate Charlie Rozencwajg.
Thomson lost his NSW Central Coast seat of Dobell at last September's election, standing as an independent but receiving less than four per cent of the primary vote.