Problem loans continue to drag on banks, with new impaired assets recognised during the June 2009 quarter the worst since the credit shock kicked off more than two years ago.APRA data published yesterday (but through the RBA in its monthly Bulletin) shows banks in Australia recognised $10.8 billion in new impaired assets in aggregate over the June 2009 quarter. This was more than a third higher than the average level of new impaired assets for each of the three preceding quarters. The June 2009 impairments are also five times as high as those recorded in the June 2008 quarter, though that low level was something of an aberration in an otherwise worsening trend.A return of some loans previously classified as impaired to performing means that the increment in impaired loans during the June quarter, at $3.6 billion, is a little less than in recent quarters.Loan write-offs by banks during the June 2009 quarter, though, were also the highest recorded, at $2.6 billion, since the strife began, and up from an average of $1.4 billion of each of the three prior quarters.The APRA data shows the ratio of impaired assets to total assets stands at 1.08 per cent at June 2009, up from 0.36 per cent at June 2008 (well into the original credit crunch but before the great collapse that occurred during the following quarter).The ratio of impaired assets to total assets reached a cyclical low in the September 2006 quarter. Impairment levels were last this high in June 1996, and were at that stage falling, fours years into the recovery from the recession of the early 1990s.The level of past-due loans was only a little worse in the June 2009 quarter than in the March 2009 quarter, at $10.4 billion.Total provisions across the sector were $20.4 billion, more than double the level a year earlier and around three times the level of provisions two years ago.