Police Minister Lisa Neville has stridently defended the force's handling of climate change activists who have accused officers of using excessive violence to break up their protests in the CBD.

Protesters and police have clashed outside the International Mining and Resources Conference at the Melbourne Exhibition Centre over the past three days.

Police use pepper spray as protesters attempt to stop conference members entering the conference on Wednesday morning. Credit:David Crosling/AAP

On Tuesday Emma Black, a spokeswoman for the protesters, claimed the police response to their blockade of the conference had been "incredibly hostile".

This month also saw days of disruptive action in the CBD by climate change activists under the Extinction Rebellion banner.