He has not been nominated and his owners would be required to pay a $15,000 late entry fee by November 4.
"The cup is not really on his agenda, but we will see how he goes at Ashburton on Monday. If he went super, there would be an option to go on to Kaikoura and then the cup," Mark Purdon, the co-trainer of Auckland Reactor, said.
The present plan is for Auckland Reactor to contest a junior free-for-all at Addington on Cup Day (November 11).
Winner of his 11 starts, all as a 3yr-old last season, he has not raced since April after a setback.
He was an impressive trial winner at Ashburton last Wednesday.
He is off the front in a 2400m discretionary handicap at Ashburton which would be his first race for six months.
The Kaikoura Cup is on November 3.
The TAB introduced Auckland Reactor to the NZ Cup fixed dividend betting in response to demand.
"We don't like taking bets on a horse that has not been nominated but we had a lot of requests from punters who claimed to have heard that he was starting in the cup," a TAB spokesman said.
Changeover is second favourite for the Cup at $3.50.
He has been entered for the Ashburton Flying Stakes on Monday.
Auckland Reactor is in the same race at Ashburton that was won three years ago by Mainland Banner.
Winner of her two previous starts that season as a 4yr-old, she carried on to win the cup at her next outing.
Tricky Woman, one of five wins for Purdon as a trainer and driver at Winton on Sunday, has been nominated for Addington on Friday night.
She is nearing the end of her racing career.
Genius, winner of his past six races, all at Alexandra Park, is back there on Friday night.
A winner from a 10m handicap last Friday over 2700m, the 9yr-old is off 20m this week.
The Rustler, an acceptor in race four at Invercargill today, is now trained by Allan Beck at Winton.
The Armbro Invasion gelding won twice when trained at Balcairn by Robbie Holmes.
