Nadhim Zahawi also told talkRADIO that the alleged plot to oust May as Tory leader will "fizzle out by Monday."
The MP was reacting to reports that Shapps and 30 other Tory MPs were plotting to trigger a vote of no confidence in May. Shapps didn't deny involvement when he spoke to talkRADIO this morning, although he blamed the Tory whips for making the plot public.
"If Grant has 30 names, he should honourably publish them," Zahawi told Julia Hartley-Brewer.
"I don't believe there are 30 names. I haven't spoken to a single colleague who has said they are part of Grant's little team.
"I think this is genuinely misguided and wrong and it will fizzle out by Monday."
Zahawi, who has made a number of public declarations of support for May, continued by saying that Shapps had "misjudged the mood of the party, both in the country and in Parliament.
I've taken so many calls from colleagues saying 'Grant is completely wrong on this.' I've had so many members text me to tell me this is completely wrong."
Although May continues to face brickbats over his disastrous conference speech, Zahawi backed her to deliver a good Brexit deal, and said her new council housing initiative was a "game-changer" which had "panicked" the Labour Party - prompting incredulity from Julia.