Apple is being sued by US e-commerce site Tiger Direct for infringing on its trademark with the launch of the latest Mac OS X, named "Tiger".

Tiger Direct's lawsuit claims Apple's use of the word tiger will mislead customers, and came just a day before the software's highly publicised launch.

Filed in Florida, the lawsuit requests a restraining order and injunction against Apple that could stop the company from distributing Mac OS X 10.4. It won't stop Apple's launch today though, since the preliminary injunction hearing is on Tuesday 3 May.

Tiger Direct, a subsidiary of Systemax, was established in 1987 and sells business and consumer computer equipment via its site and a catalogue with a monthly circulation of more than two million, the company said. The site has been listed as a top 10 e-commerce site by Nielsen Net Ratings for several years, according to Tiger Direct.

The lawsuit alleges that Apple's "Tiger" campaign is causing consumer confusion and diluting Tiger Direct's trademarks. "(Apple's) promotions refer to 'Tiger Essentials', 'Tiger Unleashed', 'Tiger World Premiere' and 'X Days until Tiger', and direct consumers to a 'Tiger Center' that features products from manufacturers and product categories which are basically the same as the offerings by Tiger Direct," said Tiger Direct in a statement.

The suit also notes that Apple's publicity has knocked out of its usual position near the top of search listings on Google and Yahoo. The company said it promotes Apple's products among thousands of others.

Separately, Cisco Systems this week confirmed that the new OS X version won't be compatible with Cisco-based virtual private networks (VPNs), creating a headache for those who connect remotely to many office networks. Apple's built-in PPTP software doesn't work with Cisco VPNs, and a Cisco VPN client available for earlier versions of OS X isn't compatible with Tiger, Cisco said.

Cisco said it has been working with Apple on Cisco VPN support for Tiger but did not complete the modifications in time. Users attempting to connect with the existing Cisco VPN client for OS X will get an error message, according to reports. Cisco said an upgrade should be available by mid-May.

The networking equipment maker said major operating system upgrades routinely require work on VPN clients to maintain compatibility, and said Cisco and Apple have a good relationship, according to reports.

Apple was not immediately available for comment.