Tory MPs have been accused of sending "deliberately misleading" to locals, which critics say suggest they come from the Green Party.
A campaign group has written to Conservative chairman Nadhim Zahawi demanding activists stop distributing the leaflets and overhaul rules about campaign material.
The leaflets, distributed across the country, feature various shades of green and include pictures of Tory MPs and their names - but without saying they are Conservatives, though there are references to the “Government”.
The senior MPs named on the leaflets include Chancellor Jeremy Hunt and former Work and Pensions Secretary Chloe Smith.
South Cambridgeshire MP Anthony Browne, West Bromwich MP Nicola Richards, Totnes MP Anthony Mangnall and High Peak's Robert Largan were all named on similar flyers in their areas.
Readers have to study hard to find the small Conservative logo at the bottom corner of the leaflets.
In a letter to Mr Zahawi, seen exclusively by the Mirror, Reform Political Advertising says the leaflets “utilise the same five-degree tilted stripe, two shades of green and typeface” as the Green Party.
Reform Political Advertising Co-Founder Alex Tait said: “We’ve written to the Conservative Party to urge them to stop producing these deliberately misleading leaflets.
At a time when faith in politics, trust in democracy, and respect for politicians is at an all-time low, dressing up your own adverts in the clothes of another party is deeply irresponsible."
He added: “As it stands, there is no mechanism in place to ensure the policies, pledges and promises parties make in their leaflets are truthful and transparent.
“It’s time we created an empowered, resourced, and effective committee to oversee political advertising and ensure it is fit for public consumption.”
The Green Party said “clearly the Conservatives’ own brand is now so bad, and Tory MPs so deeply embarrassed about their own government, that they are trying to camouflage themselves as Greens”.
Co-leader Adrian Ramsay added: “If the Conservatives really wanted to be Green, they would also pinch our popular policies such as tackling the climate emergency, standing up for public services and supporting the least well off in society.
“But unfortunately there seems little prospect of them doing that.
“Our hundreds of Green councillors across England and Wales will continue to deliver genuine Green politics, focusing minds in council chambers all over the country on greener, fairer solutions.”
Jennifer Nadel, co-director of the Compassion in Politics think tank, said: "As well as supporting Reform Political Advertising’s call for the strengthening of the rules around political adverts, we also believe there is an urgent need to safeguard the value of honesty in politics more generally.”
A Tory source dismissed the claims, saying "As far as we're aware, the Green Party don't have copyright on the colour green.”
