(Adds details about results, CEO comments in paragraph 2-3) May...

(Adds details about results, CEO comments in paragraph 2-3)

May 5 (Reuters) - ANZ Group Holdings Ltd (ANZ) on Friday edged past expectations with a 22.8% rise in first-half profit but warned of a tough second half amid stiff competition in retail banking and rising cost pressures.

"The next six months will be more difficult than the last. Competition in retail banking is as intense as it has ever been, both in Australia and New Zealand," Chief Executive Officer Shayne Elliott said.

Elliott said there were signs of "emerging stress" among its customers.

Earlier this week, the country's No. 2 lender National Australia bank (NAB) said its margins had peaked during the last half and warned of uncertainties amid a tougher credit environment ahead.

ANZ's net interest margin, a key gauge of profitability, was at 1.75% at the end of March, compared with 1.58% last year.

Margins at the Australian lender have swelled from a series of interest rate hikes by the central bank since May last year, but analysts have warned margins could plateau going forward.

Australia's fourth-largest bank said cash profit from continuing operations was A$3.82 billion ($2.56 billion) for the six months ended March 31, up from A$3.11 billion a year ago, beating a consensus estimate of A$3.81 billion.

($1 = 1.4945 Australian dollars)