With over 1.4 million units sold in the US, Nintendo says it has caused a strain on the "pipeline".

Speaking to GamePro, Nintendo has blamed huge demand for SSBB's online play for the game's poor online performance being experienced by gamers across North America.

"As with the launch of any online-enabled game, especially one as popular as Super Smash Bros. Brawl, everyone wants to play at once," a Nintendo spokesperson told GamePro. "This puts a strain on the pipeline."

The situation regarding lag and outages experienced in the Play With Anyone matches does appear to be improving, at least that's what Nintendo says.

"We have seen improvements in online play performance every day since launch," explained the Nintendo spokesperson.

There's still no confirmed European release date for Super Smash Bros. Brawl, although a summer release seems most likely.