Rod Beckstrom, chief executive of ICANN, said only 8 or 9 percent of ipv4 addresses were left, and companies needed to switch to the new standard of ipv6 as quickly as possible.
"We are running out," he told Reuters in an interview. "That move really needs to be made, we're seeing this scarce resource run down."
Ipv4, used ever since the Internet became public in the 1980s, was created with space for only a few billion addresses, whereas ipv6 has trillions.
A multitude of gadgets including cameras, music players and video-game consoles are joining computers and mobile phones in being connected to the Web, and each needs its own IP address.
Hans Vestberg, the chief executive of telecom equipment maker Ericsson, predicted earlier this year there would be 50 billion connected devices by 2020.
Beckstrom said: "It's a big management task and network operations task ... but it's going to have to happen because we humans are inventing so many devices that use the Internet now."
Beckstrom was in Moscow to officially hand over the first international domain name in the Cyrillic alphabet to Russia. Instead of having to use the Latin domain .ru, Russian organizations will now be able to use the Cyrillic equivalent.
ICANN approved the gradual introduction of internationalized domain names last year. Nations can now apply for country-level domain names in other scripts, such as Arabic or Chinese, but eventually this will be expanded to all Internet address names.
So far, aside from Russia, Egypt, Saudi Arabia and the United Arab Emirates have won ICANN approval to use their national language scripts on the top-level domain, or last part of the address after the dot.
"It's a very big move. The Internet's been around roughly for four decades and this is the first time that domain names are opening up to people's native tongues and scripts," Beckstrom said.
He said ICANN had received about 21 requests so far for international domain names (IDNs) from countries.
Beckstrom said it had taken 11 years of technical work to find a way to bring in other languages. "When the Internet was invented and when the standards were initially developed they wanted to have it available for all scripts but there wasn't a standard back then so they used ASCII or Latinate characters as a standard," he said.
ASCII is an encoding scheme that translates letters of the Latin alphabet, numbers and other symbols into the 1s and 0s that computers can understand.
"The Internet's been accessible to a lot of young people who are comfortable learning new languages or other characters but there are many people who aren't that comfortable working in other languages and character sets," said Beckstrom. "We see it really opening up to all of the world and actually the Internet becoming more truly global."
