Mr Noppadon said on Friday that any proposal to have a prime minister installed who is neutral makes for a difficult topic for discussion.
He doubted there is anyone fit for the prime minister's job who would be considered by all sides to be unquestionably neutral.
He commented after several parties attempted to broker talks between the caretaker administration and the People's Democratic Reform Committee (PDRC) anti-government protest group.
The idea of a neutral prime minister to undertake national reform before holding a general election was floated by some legal experts and favoured by the protesters.
Mr Noppadon said voters went to the polls and after that, a prime minister will be chosen. It would be hard to justify ''ditching'' the premier of the voters' choice.
Mr Noppadon, also a legal adviser to ousted prime minister Thaksin Shinawatra, said it would be a good idea to have a neutral person to broker talks between conflicting parties.
However, the talks must be held on the basis of constitutional compliance and with the full intent of preserving democracy.
No one should come to the negotiating table with preconditions, he added.