A TRIP to Disneyland in California should have been a dream for Tammy Merry and her family but a surprise on their hotel bill has turned it into a nightmare.

The family was charged $12,000 Australian dollars for valet parking of their hire car at Disney's Grand California Hotel and Spa.

An administrative error meant the US$84 cost was charged as US$8400 (which equates to AUD$12,000) - 100 times what it should have been.

"It's been a nightmare," Ms Merry told the Daily.

"I know it's a simple human error but it is hard not to be mad."

The hotel processed the refund, which will take days to clear, and offered the family "some cash" to help, and by way of an apology.

"We got a free breakfast with a few of the characters too which doesn't come cheap. The kids enjoyed that at least," she said.

The family was also offered free valet parking ongoing.

Ms Merry said the ordeal had been "a pain in the a**" but was grateful the hotel had made an effort to mitigate the mistake.

"Doesn't really cover it but it's something," Ms Merry said.