Mid Sussex MP Nicholas Soames wants to hear views on a mini-parliament, which would cover Sussex and places as far away as Milton Keynes.
The Tory MP, who is opposed to regional assemblies, said ministers would only go ahead with the proposals if the public wanted them.
They have pledged to only hold a referendum on establishing the mini-parliament - which could cost £200 million per year to run - if there is "sufficient local interest".
He is urging as many Mid Sussex voters as possible to contact him before the deadline of March 3.
Mr Soames said: "Regional government, in my view, would do nothing to give power to local people.
"Instead, decisions currently taken by county councils would be made further away, by a regional assembly with little interest in any one area."
If voters backed the idea in a referendum, East and West Sussex County Councils would be scrapped and replaced with a mini-parliament also covering Oxfordshire, Buckinghamshire, Berkshire, Hampshire, Surrey and Kent.
Brighton and Hove, which is already a unitary council, would survive in its present form.
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