AT&T has asked the US Federal Communications Commission to block the proposed merger of Sprint Nextel and Clearwire.

Clearwire and Sprint's Xohm wireless broadband unit are planning to merge in an effort to rollout WiMax services later this year.

The new company will be 51 per cent owned by Sprint, and 27 per cent by Clearwire. The remaining 22 per cent will be split between Google, Intel, Comcast, Time Warner and Bright House Networks.

AT&T's argument is that the merger application "fails to address in any meaningful way the competitive showing traditionally required by the FCC when reviewing major transactions".

The company added that "because the applications are therefore facially defective, they should be denied".

However, AT&T is currently upgrading its 3G network and is trying to block the merger as the new network will cut into its expected data revenues.

Intel and others are keen to kick-start the WiMax industry and the chip giant will be rolling out WiMax-ready kit by the second half of the year.