Having won over the famous fences once already this week, Nina Carberry has the bookies running scared with First Lieutenant ahead of the Grand National.

The price for Mouse Morris' veteran has been steadily shortening all week and a legion of Carberry fans are expected to unload.

With her dad, Tommy, and brother Paul already having won the race, she is seeking to continue her family's association with the world famous event on Saturday (Sunday AEST).

Just a few days ago champion rider Tony McCoy said it would only be a matter of time before a female jockey won the Aintree spectacular, and Carberry is top of the queue.

At the start of the week, Katie Walsh won the Irish Grand National and holds the distinction of a best National finish for a female rider when third on Seabass in 2012.

Coral expect a victory for Carberry to cost the industry millions.

"Usually you would focus on the racehorse's breeding but in this case Nina Carberry is well bred to win the Grand National," spokesman Simon Clare said.

"She is also in red-hot form having won over the National fences on Thursday on On The Fringe in the Fox Hunters' Chase.

"If Nina Carberry and First Lieutenant come home in front the nation's bookmakers will be well behind to the tune of over STG25 million ($A47.83 million) worth of losses."

The worst result for the bookies, though, would be a victory for McCoy and Shutthefrontdoor, with a win set to produce a record loss for the industry.

"We have never witnessed the level of support for one individual, in any race, not least the most competitive race in the calendar and it looks like punters from all over the world are putting their faith in AP and Shutthefrontdoor, almost to the exclusion of everything else," Betfair spokesman Barry Orr said.

"Earlier this week a conservative figure of a STG50 million industry loss has now grown to an unprecedented 75 million with the McCoy story snowballing into a global gamble."