The top U.S. communications regulator praised recent moves by top wireless companies to open their networks and said he would work to overcome a looming shortage of airwaves used by the industry.

Federal Communications Commission Chairman Julius Genachowski said on Wednesday that consumers would benefit from the latest move by AT&T Inc to open its network to Internet voice service and a partnership between Verizon Wireless and Google Inc.

In a speech to the CTIA wireless industry trade association convention in San Diego, Genachowski sympathized with wireless industry fears that the explosive growth in smartphones will lead to a shortage of airwaves.

I believe that that the biggest threat to the future of mobile in America is the looming spectrum crisis, Genachowski said.

T-Mobile, a unit of Deutsche Telekom AG, is among carriers seeking more spectrum to better compete with AT&T and Verizon Wireless, a venture of Verizon Communications Inc and Vodafone Group Plc.

Genachowski's remarks come one day after industry announcements that would allow cell phone users to make cheap calls via the Internet.

Google, the world's largest Internet search company, said it was teaming up with Verizon Wireless to co-develop multiple phones based on its Android operating system. Google's Voice application would be on the new phones.

Separately, AT&T, which has exclusive rights to Apple Inc's iPhone, said it will open its third-generation wireless network to third-party Internet voice applications, clearing the way for services such as Skype.

These are both wins for consumers, said Genachowski, who said the FCC will be vigilant in promoting competition within the wireless industry.

(Reporting by Gina Keating; Writing by John Poirier; Editing by Tim Dobbyn)