He also allegedly used the card to buy a cheap suit, to stay at a motor lodge in Hastings and to pay a veterinary bill for his horse.
The Sunday Star-Times last week obtained hundreds of pages of Horan's mother's bank statements going back to 2000. They show that Olwen Horan's cards were being hammered while she was terminally ill and bedridden before her death in August.
New Zealand First leader Winston Peters said yesterday he relied on the statements and other information to sack Horan, and again called on him to resign from Parliament.
"He's got no business being in Parliament now. He's got no mandate and no business trying to tough this out. It's appalling."
Horan continues to deny wrongdoing but did not return calls to address the latest allegations.
Olwen Horan signed an amendment to her will a month before she died authorising her executor to retrieve money loaned to her Mt Maunganui-based son or "taken by misadventure".
The Star-Times can reveal her credit card was used at the Dawson Motel in New Plymouth on May 27, 2011. Horan was in New Plymouth overnight on May 26 to attend a race meeting, and made a speech to a Grey Power meeting on behalf of Peters when Peters' flight was diverted due to bad weather.
At that point, Horan had yet to be elected to Parliament.
In August 2011, the card was used to buy a suit at Barkers menswear in Papamoa for $99. Horan had boasted at the time about it being a bargain. The card was used at the store again in July this year to buy $990 worth of clothes.
Horan also used his mother's card to pay $300 for accommodation at the Omahu Motor Lodge in Hastings in October 2007.