AUBURN – Charging lapses in procedures and an excess of municipal authority, the developer behind the Hilton Garden Inn is challenging the city’s permission of a rival hotel.

RiverWatch LLC, the development company headed by Lee Griswold that opened the Hilton in 2003, filed an appeal with Androscoggin County Superior Court on May 6, asking the court to invalidate the city’s Planning Board approval for a new 110-room hotel at Great Falls on Turner Street.

The $12 million hotel, a Hampton Inn, is under development by Mullaney Hospitality Group and Great Falls Plaza Development Corp. The project received Planning Board approval April 8 after a marathon public hearing that started March 11, then was tabled to allow GFP Development to supply additional information. The public hearing reconvened on April 8, and the project was approved unanimously by the board.

“We are reviewing the complaint and formulating our response,” said Laurie Smith, interim city manager. The complaint is with the city’s attorneys at Bernstein and Shur.

Steve Myers, spokesman for GFP Development, said his company has also reviewed the complaint, which he called “frivolous and without merit.”

“It’s simply a stalling tactic,” he said. “They are trying to prevent another hotel in downtown Auburn.”

Myers said GFP has been performing design and engineering work on the site since the Planning Board granted its application for the hotel, which included plans for a municipal garage and bus station. He said he spoke with Bill Mullaney of the Long Island-based hospitality company, on Monday.

“We believe we’ll both be going forward as planned,” Myers said.

The complaint cited nine specific actions by the Planning Board that violated its customary procedures and authority. Among the charges are that it did not specifically waive setback requirements for the garage; failed to require an enclosure for roof-top mechanical equipment on the hotel; failed to require a statement from Mullaney attesting to its financial resources; and approved the project without a new traffic movement permit or proper conditions for loading zones and lights.

The complaint also said the board erred by allowing two members who were not present at the March 11 portion of the public hearing to vote on the application April 8, and other procedural missteps.

The complaint asks the court to invalidate the Planning Board’s approval and instruct it to either deny the project’s application or require that it be resubmitted.

“We are confident the city acted appropriately,” Myers said of the allegations.

Smith said she believed the board followed its normal procedures in handling the application.

Planning Board members acknowledged during the nine hours of public hearing that it was an awkward situation, due in part to the city’s status as a co-applicant in the project. GFP Development and Mullaney plan to build the hotel, while the city would build the 300-space municipal garage parallel to railroad tracks.

Many of the allegations made in the complaint were raised by RiverWatch attorney Elliott Epstein during the public hearing. Both sides are expected to file their responses within a month.