Senior Victorian police have defended their tactics, including pushing a journalist, during demonstrations outside a mining conference in Melbourne, saying officers were not "heavy handed" in the face of "more violent" protesters.

Key points: Commander Libby Murphy said footage of police pushing a journalist was "probably not the full story"

Commander Libby Murphy said footage of police pushing a journalist was "probably not the full story" She defended the use of pepper spray and said many activists were not peaceful

She defended the use of pepper spray and said many activists were not peaceful Police and protesters are preparing to return to the venue on Thursday for a final day of demonstrations

Scuffles broke out between officers and demonstrators outside the International Mining and Resources Conference (IMARC), as about 300 climate activists tried to blockade the event.

Police arrested 17 people on Wednesday and used horses and pepper spray to break up the climate activists, who had massed at the Melbourne Exhibition and Convention Centre for the third day in a row.

Commander Libby Murphy said protesters had turned "more violent" and she thanked police at the scene for their "restraint".

Two protesters scaled the building, and Commander Murphy said one faced charges for climbing a pole and endangering others.

A Channel 7 journalist, Paul Dowsley, was also pushed by police as tensions hit a high.

Loading

Dowsley said on Twitter he was obeying a direction to move to another area.

But Commander Murphy said the reporter was trying to "push through" into an unsafe area and was asked twice to move, but refused.

"It required us to physically remove him from a particular area, so the footage that you have seen is probably not the full story," she said.

Police used pepper spray to control protesters. ( AAP: Craig Golding )

She said the force would be ready to respond in the same way on Thursday when the mining conference entered its final day.

"Victoria Police's view is that we are not heavy handed and we're responding to the actions that the protesters have initiated," Commander Murphy said.

"We are doing things lawfully and we are doing things in line with policy and anything that is of a concern to anyone we will review and make our own assessment."

She defended the use pepper spray, saying protesters were endangering themselves and others, and many of the activists were far from peaceful.

"I've seen footage of some of the protesters spitting at attendees of the conference," she said.

Protesters began the morning by surging towards one of the venue's entrances, trying to prevent delegates from entering.

Police guarded the venue behind plastic water-filled barriers, which were set up in the forecourt of the convention centre to keep protesters further away from entrances to the venue.

A woman glued herself to the driveway but was later removed by police. ( AAP: David Crosling )

Mounted police tried to disperse the demonstrators, yelling at them to move as the protesters chanted "get those animals off the horses".

Earlier, protest organiser Jerome Small said the police action was "over the top", but "that's to be expected".

He said the demonstration was an "excellent display of extraordinary people".

"We said to the whole world we would link our arms and obstruct access to this gathering of climate and corporate criminals," Mr Small said.

A protester was dragged away by police. ( AAP: David Crosling )

In the morning, Police Minister Lisa Neville said she was "100 per cent comfortable" with police action.

"They are allowing people to peacefully protest, which we are not seeing … and allowing people to go about their day-to-day business without being affected," she told ABC Radio Melbourne.

"Surrounding conference attendees is just inappropriate behaviour.

"I commend them [police]. Without police being there, those protesters would be surrounding and making it physically dangerous for those people attempting to attend a legal conference in Victoria."

Sorry, this audio has expired Police Minister Lisa Neville tells Virginia Trioli she is "100 per cent comfortable" with the police action.

Police confirmed the protest was not a designated area, which would have given officers the right to remove masks worn by protesters.

But at least one officer was seen trying to remove a demonstrator's mask on Wednesday morning.

A police media spokesman said no formal complaints had been made and footage would be reviewed to ensure any action taken by officers was appropriate.

A police officer tried to take off a protester's mask in the morning. ( ABC News: Patrick Rocca )

Greens Leader Samantha Ratnam — who was at the protest on Tuesday — said the protesters were well behaved but police had used "excessive force".

But Premier Daniel Andrews vehemently defended the work of police and labelled the behaviour of protesters "appalling".

The venue, by the Yarra River, was the scene of violent clashes between about 250 protesters and more than 300 police on Tuesday. Police arrested 47 people, including two accused of assaulting a police horse.

Two police and one protester needed hospital treatment after being injured in the clashes.

Commander Murphy said a protester who was accidentally trodden on by a police horse during Tuesday's protest had suffered minor bruising but had not suffered any broken bones, contradicting the claims of some protesters.

She said police officers who on Tuesday suffered injuries, including a dislocated finger and an eye laceration, were all home safe and well.