BERLIN (Reuters) - Deutsche Bank's top management should waive executive bonuses for a second year if the lender's results remain poor, retail bank head Christian Sewing told Bild in comments published on Wednesday.

"What's clear is that if we don't pay our shareholders a dividend, then our own bonus must be put up for debate," the newspaper quoted Sewing as saying.

Germany's biggest lender has warned it may need deeper cost cuts to turn itself around after profit and revenue fell sharply in the second quarter amid challenging markets and low interest rates.

Deutsche Bank's top management earlier this year denied itself bonus payments for 2015.

The lender is standing by its plans to sell retail unit Postbank, although it is under no pressure to divest the division, Sewing added.

"The price must be right," the executive said. "We can wait."

Deutsche Bank said last year it wanted to sell Postbank, mainly to free up regulatory capital, but Chief Executive John Cryan acknowledged in May that a flotation would be challenging in the current capital market environment.

Sewing ruled out that the lender would impose penalty interest on private customers as the European Central Bank is keeping its main refinancing rate at 0 percent and the rate on bank overnight deposits in negative territory.

But many German banks will be forced to raise account maintenance charges, Sewing said, without being more specific.

Interest rates in the euro zone will remain low for at least three more years, he said, adding that rates may likely rebound to 1 percent or higher levels after that period.

Although Deutsche Bank showed a weaker reading last month in the European Union's banking stress test than most of its peers, the bank is completely stable, Sewing said.

"Our capital is sufficient and satisfactory," he said. "The question of a capital increase is not an issue at the moment."

(Reporting by Andreas Cremer; Editing by Peter Cooney)