** Shares of National Australia Bank NAB.AX rise as much as 4.4% to A$36.840, their highest level since February 19

** Stock posts its biggest intraday pct gain since April 10

** Australia's third-largest mortgage lender reported cash earnings of A$3.58 billion ($2.33 billion) for the six months ended March 31, which beat Visible Alpha consensus estimate of A$3.48 billion

** Co declares interim dividend of 85 Australian cents per share vs 84 Au cents apiece declared a year ago

** Stock has fallen 4.9% this year, as of 0035 GMT

(Reporting by Roshan Thomas in Bengaluru)

((Roshan.Thomas@thomsonreuters.com))