Orange Order leaders are refusing to comply with parading rules over next week's Drumcree church march in Portadown.
With only days left before the deadline, the Parades Commission said the district officers have still not submitted the official form, known as an 11-bar-one, for the demonstration.
By this stage the commission would normally have already adjudicated on the parade, which has not been allowed to take its formerly traditional route along the mainly nationalist Garvaghy Road since 1998.
Yesterday district master Daryll Hewitt confirmed: "The form has not yet been submitted and I cannot at this stage say whether it will be.
"If it isn't, then next Sunday will be an illegal parade, and myself and other officers are liable to be arrested."
It is the first time district officers have decided not to stick to the procedures, but they are to meet during this week to review their approach, and an 11th-hour application could still be processed.
Their toughening stance comes, however, after further deciding to double their weekly protest parades after commission chairman Peter Osborne urged the Portadown leaders to consider calling off their token march every Sunday.
Now, after this year's July 12th, they will also hold the 'mini-walk' from the church every Wednesday.
The Portadown lodge has also been angered after Mr Osborne said it would meet officers, but only after this year's Twelfth demonstrations.
"There have been a number of republican parades in recent times which did not fill out the 11-bar-one forms and there were no prosecutions in those cases," said Mr Hewitt.
"There was one in Lurgan in late January or early February and another illegal parade in Armagh."
A statement from the commission said: "The chair and commissioners met with Portadown district earlier this year and they have met with a number of interested parties in relation to parading in Portadown during the year.
"Last week commissioners met with Portadown district and the commission chairman has provided an open diary from July 18 for a meeting with Mr Hewitt."
The pre-Twelfth Orange church parade from Drumcree dates back more than 200 years. But the parade has been banned from completing the march via its 'traditional route' of Garvaghy Road since 1998.
In the previous three years, attempts to halt the parade sparked major rioting resulting in a number of deaths.