The largest marches take place on 12 July
All those involved in Twelfth parades should ensure marches pass off peacefully and without incident, the Parade Commission has said.
Chairman Roger Poole said local dialogue had resulted in the successful resolution of the parading issue in some previously contentious areas.
He said it was vital that marches and protests were carried out in a dignified manner.
This would help dialogue to continue and be replicated elsewhere, he said.
"The sectarian attacks which have taken place this week are the work of a small minority on both sides who are determined to make trouble over the Twelfth," Mr Poole said.
"These criminal attacks are clearly designed to stir up sectarian strife over the summer and are to be condemned.
"I urge all of those involved in parading and associated protests to ensure that the acts of these small minorities do not succeed in rachetting-up sectarian tensions."
Mr Poole said there still remained a number of organisations not currently engaged with the commission.
"This situation serves no-one's best interests and I would urge these organisations to enter into dialogue at the earliest opportunity.
"Finally, I would like to commend the many individuals and groups across Northern Ireland from all communities who have worked hard throughout the year to ensure a peaceful parading season."