Chancellor Philip Hammond has been told that he needs to reassure MPs on the Environmental Audit Committee that the Treasury is not trying to blunt the effectiveness of a new environment watchdog.
Committee chair Mary Creagh said Hammond or another Treasury minister should give evidence on the matter.
The row followed statements by environment secretary Michael Gove that leaving the EU would not lead to a weakening of environmental standards and that a new body would be established to oversee regulations that are at present the responsibility of the EU.
Creagh said in her letter to Hammond: “It has been widely reported that the Treasury opposed giving the environmental watchdog powers like the European Commission’s to initiate enforcement action against the government.”
The government earlier this month launched a consultation on how the new body could work and the committee is holding an inquiry into this.
Creagh said when that launched earlier this month: “The EU’s role in holding successive governments to account has transformed the UK from the ‘dirty man’ of Europe in the 1970s, to a world leader on the environment.
“Ministers must ensure that our treasured natural spaces and iconic British species, and our ability to hold the government to account on air pollution are not lost by leaving the EU.”