The right-leaning Institute of Public Affairs has joined the Greens, charities and activist group GetUp! in slamming the Turnbull government's "unprecedented and dangerous" bid to clean up the political donations system.

The think tank, which is often aligned with the Coalition on key policy questions, blasted the plan as unnecessary and excessive, arguing the legislation was so poorly drafted as to go "way beyond" its declared aims.

Under the bill, any group spending more than $100,000 advocating on potential election issues will be subject to the new disclosure laws. Credit:Jessica Shapiro

Under the bill before Parliament, political parties, associated entities and all organisations engaged in political advocacy would be banned from receiving foreign donations, and would be subject to more rigorous disclosure and transparency requirements.

IPA research fellow Gideon Rozner, who advised former special minister of state Michael Ronaldson during the Abbott government, said the potential reach of the bill was "extremely concerning" and could effectively silence contributions to the public debate.