Jon Van Dyke, a University of Hawaii law professor and leading authority on Native Hawaiian law and constitutional law, died Tuesday night while traveling in Australia, a spokeswoman for the UH Richardson School of Law confirmed. He was 68.

"Hawaii has lost a steadfast advocate for Native Hawaiian and civil rights, a leading expert on Hawaiian land and water rights law, and a tireless defender of public lands and natural resources," U.S. Sen. Daniel Akaka said.

Van Dyke’s death was unexpected, and he died in his sleep during a trip to a conference on ocean-related law in Melbourne, Australia. Van Dyke had been expected to deliver the keynote speech, and organizers of the conference realized something was wrong when he didn’t show up to deliver the address, said Avi Soifer, dean of the UH law school.

Soifer described Van Dyke as a low-key, but brilliant professor, researcher and educator who excelled in a multiple areas of law, including Native Hawaiian rights, human rights, constitutional law and international law related to islands and the sea.

"Jon always stood up for what he felt was pono — right and just," Akaka said. "He was an inspiration for our community and his students. Because of Jon’s work, the principle of protecting our cultural and historic resources has been preserved, and the tradition of sharing the resources of our beautiful beaches and other natural resources with all continues to be honored."

The law school is holding a memorials today during Van Dyke’s regularly scheduled constitutional law class at 1:30 p.m. and 5:30 p.m. and members of the law school community are invited to gather in the moot courtroom all day to mourn, share stories and sign a book of condolences.

As a young law professor Van Dyke was deeply involved in the 1978 state Constitutional Convention, a pivotal turning point in modern Hawaii politics. The convention led to the establishment of the state Office of Hawaiian Affairs to try to provide redress to the Hawaiian people, Soifer said.

Van Dyke had sparkling blue eyes and a relaxed, questioning style of engaging with students and acquaintances. "He didn’t flaunt his knowledge, but you would quickly find out how deep his knowledge was in lots of different areas," Soifer said.

Van Dyke joined the UH law school in 1976 and was one of the longest-serving members of the faculty. He previously taught at the Hastings College of Law, University of California, San Francisco, and at the Catholic University Law School, Washington, D.C.

"I find it virtually impossible to think about the law school and our community without picturing Jon working away and bringing his extraordinary array of different skills to bear on all kinds of genuinely important projects and commitments," Soifer said in an e-mail to students.

Van Dyke was author of six books, including  "Who Owns the Crown Lands of Hawaii?" in 2008, "Jury Selection Procedures: Our Uncertain Commitment to Representative Panels" in 1977, and "North Vietnam’s Strategy for Survival" in 1972. He was also editor of five additional volumes related to issues surrounding law of the sea.

He served as the law school’s associate dean from 1980 to 1982. He was also director of the Spark M. Matsunaga Institute for Peace from 1988 to 1990, and was an adjunct research associate or fellow at the East-West Center from 1979 to 1991, and from 2000 to 2011, according to his biography.

Van Dyke was recipient of a UH presidential citation for excellence in teaching in 1987, and was selected outstanding professor at the law school on four occasions.

He graduated from Harvard Law School in 1967.

Van Dyke is survived by his wife, attorney Sherry Broder; two sons, Jesse Broder Van Dyke, a spokesman for  Akaka, and Eric; and daughter Michelle.