NEW YORK — A New Zealand lawyer long active on Internet addressing policies was elected yesterday as the first non-American chairman of a key oversight agency, replacing Internet pioneer Vint Cerf.

The board of the Internet Corporation for Assigned Names and Numbers selected Peter Dengate Thrush, 52, over telecommunications expert Roberto Gaetano, of Italy, to head the nine-year-old agency tasked with handling domain names and issues related to allowing Internet computers to find Web sites and route e-mail.

Gaetano, 57, remains ICANN's vice chairman.

The selections come as ICANN begins testing domain names in other languages and could help blunt any criticisms that the organization is U.S.-centric, given its headquarters in Marina del Rey, Calif., and the veto power the U.S. Commerce Department yields over it.

"It will make it harder for those complaining to say it's totally U.S.-dominated, which it isn't but it certainly looked that way," former ICANN Chairwoman Esther Dyson said.

Cerf said the international mix in ICANN's leadership "is just simply a sign of the increasing globalization of the network."

Cerf, 64, who in the 1970s co-invented the communications protocols that serve as the Internet's foundation, stepped down from ICANN yesterday because of term limits. He was ICANN's second and longest-serving chairman, having been first elected to the position in 2000.

"To those who now guide its path into the future comes the challenge to fashion an enduring institution on this solid foundation," Cerf said before stepping down. "I am confident that this goal is not only attainable, it is now also necessary. The opportunity is there: Make it so."