The Christian Institute says the Conservatives have "a lot of questions to answer" about their plans for a 'Commission for Countering Extremism'.
Colin Hart, Director of The Christian Institute, said: "If the Conservatives do form the next government and they press ahead with this Commission, they'll have to be very careful about who they appoint and what their mandate will be. It's no good filling it with politically correct zealots using their new powers to denounce their ideological opponents.
"Government lawyers will need to warn committee members that using the nebulous and indefinable concept of 'extremism' on its own as a basis for taking away freedoms is a serious risk to civil liberty.
"The word 'extremist' has been robbed of all meaning by activists who insist on using it to smear anyone who disagrees with them.
The Institute warns that there has already been a series of witch-hunts against people holding traditional views and that there are plenty of commentators and civil servants who already see mainstream, orthodox Christian views as dangerous.
Colin Hart continues: "This Commission on extremism might make a bad situation a whole lot worse.
"People labelled extremists in their own day include Martin Luther King, Rosa Parks, Harriet Beecher Stowe, William Wilberforce and the Tolpuddle Martyrs. Today, people like Germaine Greer and Dame Jenni Murray are vilified for 'extreme' views on transsexualism that actually represent the views of the great majority of people."
The Christian Institute is a non-denominational registered charity, which seeks to promote the Christian faith in the UK.