The lawyer for a woman charged after violent protests outside a Melbourne mining conference says he's concerned about gaps in police body-camera footage from the event.

Sheridan Vautier, from NSW, was one of more than 30 activists to face Melbourne Magistrates Court on Monday, charged with obstruction and other offences related to last month's anti-mining protest outside the Convention Centre.

Protesters outside Melbourne Magistrates Court on Monday morning. Credit:AAP

Her barrister Gideon Boas told the court he was "considerably concerned" that police cameras appeared to have been switched on and off during the protest.

Ms Vautier, 23, was charged with intentionally obstructing and resisting an emergency worker on duty.