A U.S. judge has stated that Samsung's Galaxy tablets breach Apple Inc's iPad patents, but added that Apple has a problem establishing the validity of its patents in the latest courtroom face-off between the technology giants.

U.S. district judge Lucy Koh made the comments in a court hearing Thursday, but has yet to rule on Apple's request to bar some Galaxy products from being sold in the United States.

Samsung attorney Kathleen Sullivan argued that in order to defeat an injunction bid, Samsung only needs to show that it has raised strong enough questions about the validity of Apple's patents.

The judge frequently remarked on how similar the two tablets were, at one point during the hearing holding both up above her head asking Samsung attorney Kathleen Sullivan if she could identify the Samsung tablet.

Apple and Samsung are quickly becoming top rivals in the business. The increasing demand and prospects of the Samsung devices have led Apple to resort to suing Samsung and seeking to stop sales worldwide. Samsung has responded by seeking a ban on the sales of Apple's iPhone 4S, charging that the iPhones and the iPad 2 are violating the multiple wireless technology patents it holds.

Earlier, Apple has won a preliminary sales injunction against Samsung in Australia to block Galaxy Tab 10.1 from hitting the stores. This will leave the Korean company with no choice but to either face a 2012 trial or scrap the tablet altogether. The federal court judge decided in favor of Apple's claims that Samsung infringed on two of its patents.