Adam Afriyie's plan to steer leadership-backed legislation on an EU referendum through Parliament has been criticised by fellow Tory MP James Wharton.
Wharton suggested the move would delay and even "kill" the private member's bill he introduced in July, and hoped Afriyie would "rethink" his approach.
He said: "We need to build as broad a base of support for the bill as we can if we are to get it through Parliament and the policy of a renegotiation, followed by an in/out referendum, is the right one to do that and the right one for the country.
"I hope MPs will decline to support it as the ultimate impact might well be to kill my bill, which would only help those who don't want any referendum at all."
MPs will today debate a private members' bill on an EU referendum brought by the Conservative MP for Stockton South, James Warton.
At 29, the former solicitor is the youngest Conservative MP. He was among the 114 Tory MPs to vote in favour of an amendment to the Queen's Speech in May.