Saddle Views Estate Ltd director and quarry owner Calvin Fisher said a letter a local MP - later confirmed to be Ms Curran - sent to the court amounted to her attempting to "influence a judge prior to a hearing'' and was "reprehensible''.
"I am shocked at the way people have tried to manipulate the process,'' Mr Fisher said.
University of Otago parliamentary law specialist Marcelo Rodriguez Ferrere said Ms Curran's letter was unusual and not the most appropriate way for her to represent her constituents' concerns.
Ms Curran defended the letter yesterday, saying she was merely acting as a local MP representing the concerns of her constituency.
This comes as Environment Court Judge Jon Jackson said in a minute issued yesterday the court was "highly likely'' to release a decision over what quarrying is allowed at Saddle Hill by the end of next week.
The minute also confirmed Ms Curran sent the court a letter last year urging it to take into account concern from the Dunedin public about the issue and the "precarious condition'' of the Saddle Hill ridge-line.
Judge Jackson said the parties were "promptly'' advised of Ms Curran's letter, and correspondence from Saddle Hill Community Board chairman Scott Weatherall seeking an update on the case, and told both pieces of correspondence would be disregarded by the court.
In a separate minute supplied to the Otago Daily Times, Judge Jackson said Ms Curran "could be seen as attempting to influence the court'' in the letter.
"The parties can be assured that no consideration or weight will be given to the letter,'' he said.
The case rests with the Environment Court after the High Court ruled in late 2014 the quarry had resource consent from 1960 to quarry Jaffray Hill, when Downer began using an existing quarry for material used to build Dunedin Airport at Momona.
The court heard arguments from the council and Saddle Views Estate last May after the two parties failed to agree on the extent of conditions and the scope of the quarrying.
Mr Fisher called Ms Curran's letter, dated March 31 last year, a "desperate act'' and said she should have known the dates for a hearing in May had already been set.
"Clare Curran tried to use her position as [an MP] to clearly influence the judge prior to the case taking place,'' he said.
Mr Fisher also took issue with Mr Weatherall seeking an update on when a decision would be made.
Ms Curran said she was simply doing her job as a local MP.
"I am the local MP, I have been representing constituents on this matter for almost as long as I have been in Parliament,'' she said.
She had written to Judge Jackson earlier in the process, in 2013, expressing concern about the delays releasing findings and the court had replied.
Mr Rodriguez Ferrere said Ms Curran's letter was a "little odd''.
"I haven't heard of this happening before,'' he said.
"It may have been good intentioned, I think it may have been coming from a good place, but I don't see this as the usual course of [action] and it doesn't seem to be a particularly appropriate thing to do.''
Mr Weatherall said he could not see any issue with requesting an update from the
court on when a decision would be made.
The case rests with the Environment Court after the High Court ruled in late 2014 the quarry had resource consent from 1960 to quarry Jaffray Hill, when Downer began using an existing quarry for material used to build Dunedin Airport at Momona.
The court heard arguments from the council and Saddle Views Estate last May after the two parties failed to reach a consensus of the extent of conditions and the scope of the quarrying.
