Kemi Badenoch and Robert Jenrick have been urged to set out their plans for bold environmental action.
The Conservative Environment Network has written a letter to the Tory leadership candidates which has been signed by more than 400 members.
The letter insists that a green plan would help win back potential voters.
It says: “As conservatives, we have a moral responsibility to build a brighter future for current generations and those to come. Environmental action is an inherent part of this.
“This is why successive Conservative governments have shown leadership on the environment.
“We are calling on you to lay claim to this proud legacy, champion this core conservative value, and set out your vision for ambitious environmental action.
“We know the environment matters to the majority of potential Conservative voters.
“Having a positive, practical plan for the environment would help convince people that a refreshed Conservative Party aligns with their values and win back their trust.”
The letter adds that when Tories “set out a positive environmental vision, they are rewarded with electoral success”.
The letter says: “Whatever coalition of voters the party seeks to build ahead of the next general election, there can be no doubt that a strong environmental platform will be a net electoral asset.
“We urge you to set out an ambitious plan on the environment that is rooted in our conservative principles, to deliver a brighter future for us now and generations to come.”
Conservative members have until October 31 to vote for Ms Badenoch and Mr Jenrick, who are both on the right of the party, with the result announced on November 2.