A young opponent of the Electoral Finance Bill was taken aback when Education Minister Chris Carter replied with an email asking: "Are you a member of the Exclusive Brethren?"
Simeon Brown has emailed all MPs several times asking them not to support the bill and saying it restricts freedom of speech.
He twice got a response from Mr Carter asking if he belonged to the brethren.
Mr Brown, 16, said he was disappointed at the response, which bordered on religious discrimination.
"I asked him how my response to this provocative question would change his response to me. How would it be different if I was Exclusive Brethren, or just a concerned citizen, like me?
"You don't expect that from ministers. You expect them to be a little bit helpful, and outline their reasons for supporting the legislation."
Mr Carter did not know Mr Brown's age, or his religious affiliations - the teenager is a Reformed Baptist - but said Christianity was not part of the submissions he made.
A spokeswoman for Mr Carter said the question was the minister's standard response to messages against the Electoral Finance Bill.
"He was making a point about people trying to buy elections. He's trying to make the point that the Exclusive Brethren tried to influence the 2005 election secretly."