TV writer Kay Mellor has objected to plans to sell off greenbelt land in Leeds to fund a £40m expansion of Headingley Stadium.
Proposals to build new stands and turnstiles at the ground were submitted to the council in April by Yorkshire County Cricket Club and Leeds Rhinos.
The rugby club wants to sell its land in Tingley and Weetwood to housing developers to fund the project.
Leeds-born Mellor, who wrote ITV's Band of Gold, said it was "a veiled threat".
Under the plans, the sports clubs want to demolish and rebuild two existing stands and turnstiles and create new car parking facilities at the shared stadium.
More than 500 letters have been sent opposing the sale.
Leeds Rhinos said the sale of the two plots would "create over 200 new homes in the city with 100% of the net receipts from the sale of the site being invested in the improvements" of Headingley.
In her letter, Mellor, who also wrote for Coronation Street and Brookside, said: "...I feel a responsibility to protect the beneficial and beautiful green belt we have, not only for my generation but also for my children and my grandchildren's generation. I think it is my God-given duty."
She continued to write that the sale of the two plots, known locally as Tetley field, would "have a permanent and irreparable impact on our community and the green belt".
"It is inappropriate and an aggressive tactic to even suggest harming the green belt and leisure assets in the Meanwood Valley Urban Green corridor to build houses which are not needed in this area," she said.
"Trust me Headingley stadium will develop without destroying the environment elsewhere. The cash tills will still ring with entrance money pouring into the stadium owners pocket..."