The S&P/ASX 200 index ended up 0.6 percent at 5,811.0, having earlier touched 5,819.1 - a high not seen since May 2008. The index has risen 9.5 percent in 11 sessions, a feat not seen in over five years.
A late rally in bank stocks helped offset losses in the energy sector, which fell on a renewed slide in oil prices.
Commonwealth Bank reached A$93.29, while Westpac Bank hit A$36.54. ANZ retested its all-time high of $35.07 first reached nearly a year ago.
National Australia Bank, which reported a 6 percent gain in first-quarter cash profit, climbed to a 15-month high of A$37.03. However, it was still some way off its record peak of $44.84 set back in 2007.
New Zealand's benchmark NZX 50 index rose 0.2 percent, or 12.3 points, to finish at 5,797.6.