Struggling plastic clog maker Crocs Inc is caught up in a legal battle with German car-maker Porsche over the use of the name Cayman on its best-known footwear line.

Crocs, which sells its colourful shoes in 125 countries, admitted in the Form 10-Q filing that accompanied its third-quarter results earlier this month that Porsche is suing it for alleged trademark infringement.

The automotive maker wants Crocs to stop selling its Cayman shoes in Germany, because Porsche has already registered the brand for one of its popular sports car models.

Porsche also wants Crocs to pay its attorney's fees.

In its filing, Crocs says it intends to "vigorously defend itself against these claims."