According to some Japanese sources, Sony’s long-promised date of May 31 for the restoration of all PlayStation Network services now comes with some caveats.

In a presentation for investors on Thursday following the release of its fiscal year 2010 results, a Sony representative commented on the status of its PlayStation Network online service.

“We have not changed our target date of full restoration within the month of May,” AV Watch quotes a Sony representative as saying. “In the U.S. and Europe, service has been partially restored. In Japan and Asia, while we cannot give a precise date, we hope to restore service in the coming days. Anyway, it’ll be in May. And even if we’re late on that, it’ll only be by a matter of days.”

In other words, PlayStation Network will definitely absolutely be restored by May 31, unless it isn’t.

PlayStation Network’s outage entered its sixth week Thursday, following a security breach in mid-April that caused Sony to take the service down for extensive fixes. PSN is partially online in the U.S. and Europe, but remains fully offline in Asia.

Update: Sony said Friday that it would begin to restore partial PSN services in Asia on May 28.

Image: Sony