Wellington councillor Alison Conn, the National Party's Dubbo Electorate Council Secretary, has resigned after Mr Grant likened protestors against forced amalgamations to characters from the TV show, The Simpsons.

In a recent radio interview about the proposed merger of Wellington and Dubbo councils, Mr Grant said he was: "disappointed in the two mayors (Dubbo and Wellington) who are trying to rally up a mob-mentality approach to this boundary commission process. That is going to influence nothing. It is going to actually change nothing? Forget about silly t-shirts and public meetings to rally and cheer and clap like it is an episode of The Simpsons."

Ms Conn said his comments left her with no choice but to leave the National Party.

Opposition Minister for Local Government Peter Primrose said that for the Deputy Premier to insult his constituents by comparing them to The Simpsons was pretty low.

"Troy Grant's attitude is representative of this government - absolute ignorance, and total arrogance," he said.

"Her resignation has exposed deep divisions within the Liberal/National Coalition over the issue of forced amalgamations.

"It also illustrates how out of touch both Mr Grant and Premier Mike Baird are on an issue that is running hot in communities.

"It just shows how out of touch Troy Grant is with the community who are outraged at the way this government is forcing amalgamation down people's throats," Mr Primrose said adding that Premier Baird did not consult the local community before he made his forced merger announcements.

"Now the government is insulting local people who say they disagree with them."