The state Supreme Court on Thursday heard oral arguments in a case that has the potential to play a huge role on whether the Thirty Meter Telescope is built in Hawaii.

The court must decide whether a Hawaii island man was denied the right to a hearing over the sublease the University of Hawaii intended to enter with TMT International Observatory LLC for the planned telescope near the summit of Mauna Kea.

The state Board of Land and Natural Resources denied a 2014 petition for a contested case hearing from E. Kalani Flores, who was also a petitioner in the recently concluded contested case hearing regarding the TMT’s conservation district use permit. That case is also before the state Supreme Court.

Flores, a Native Hawaiian cultural practitioner, appealed to the Environmental Court of the Third Circuit, which ruled that BLNR’s denial infringed upon his constitutional right to due process. The state then appealed to the high court.

If the Supreme Court rules that Flores is entitled to a contest case hearing, the process could delay the project for a year or two and effectively drive the $1.4 billion project to the Canary Islands.

TMT officials have maintained that they want to decide by April whether to build the cutting-edge telescope either on Mauna Kea, their first choice, or on a mountain on La Palma island in the Canaries, their alternate choice.

“It could be a huge step — or it could be a minor footnote,” UH spokesman Dan Meisenzahl said of the high court decision, depending on the outcome.

The justices Thursday asked pointed questions on both sides of the issue and didn’t seem to signal which way they are leaning, observers said.

State Solicitor General Clyde Wadsworth told the justices that under Hawaii law the sublease consent won’t affect Flores’ right to exercise his cultural practices, and there is no risk he will be deprived of that right.

Wadsworth said the bottom line for Flores is his complaints with the TMT and how it will affect his cultural practice. But those issues, he said, already have been thoroughly addressed and evaluated in the lengthy and recently concluded conservation district use permit hearing, of which he is a party.

“In these circumstances, due process does not require another contested case hearing,” he said.

But Flores’ attorney, David Kauila Kopper with the Native Hawaiian Legal Corp., expressed doubt his client’s rights will necessarily be protected.

“The state cannot fulfill its obligation to protect the rights of Native Hawaiians if it refuses to be informed before it acts,” he said.

“When held before decision making, contested case hearings allow state agencies to be informed of the facts of its decisions on the rights of the public. But when this procedure is ignored, the state risks the deprivation of these rights without due process,” Kopper said.

Much of the argument centered on whether Flores’ request for the contested case hearing meets a legal test established in the court’s 1989 ruling in Sandy Beach Defense Fund v. the Honolulu City Council. The case involved the request for a contested case hearing in the issuance of a Special Management Area use permit for the proposed development of 200 single-family homes near Sandy Beach Park on Oahu.

The test calls for the balancing of three factors: the private interest that would be affected, the risk of an erroneous deprivation of that interest, and the governmental interest, including the toll of additional procedural safeguards.

Whether Flores’ request met the test depended on who was arguing.

Afterward, Kopper said he remained positive about the hearing.

“This case is about the right to be heard in agency decision making, especially the right for Native Hawaiians to be heard,” he said.

TMT International Observatory attorney Doug Ing added, “We’re very pleased the legal process is proceeding, and we are hopeful the court will render a decision that will allow us to begin construction.”

TMT petitioner Kealoha Pisciotta said the university has demonstrated a history of violating Native Hawaiian rights, and contested case hearings have become a necessity for helping to keep state agencies informed about what those rights are.

The sublease covers the 18-story observatory construction site and an access road for a total of roughly 8 acres on Mauna Kea’s Northern Plateau near the summit. UH’s 1967 master lease of more than 11,000 acres at the summit requires the board’s consent before it can sublease.

Meanwhile the conservation district use permit appeal is winding its way through the process at the state Supreme Court. The high court has already received written briefs from TMT foes and is now awaiting briefs from BLNR, the university and TMT, followed by responses from the appellants.

The BLNR in September approved the recommendation of retired Judge Riki May Amano, following a 44-day contested case hearing, to approve the TMT conservation district use permit allowing construction.