Kiwibank reported a 53 per cent rise in first-half profit, but says its need for capital to back strong lending growth means it still needs to raise extra capital in the next year or two.Kiwibank's chief executive, Paul Brock, told a news conference announcing the result that Kiwibank was still not generating enough profit for organic capital growth to comfortably sustain the bank's growth.Brock said Kiwibank was in discussions with its share-holder, the government-owned New Zealand Post, about continuing to raise fresh capital."The hybrid tier-one option is one option we'll have a look at," Brock said.Kiwibank raised NZ$150 million through a BB+ rated tier-two subordinated bond issue in December. It increased its tier-one capital ratio to 13.5 per cent at December 31, from 12 per cent a year earlier, through retained earnings and the tier-two issue.Net profit for the six months to December was NZ$58 million - up from NZ$38 million in the previous corresponding period.Net interest income grew 13.8 per cent, to NZ$140 million, for the half, while other income grew 7.4 per cent, to NZ$87 million. Operating costs grew 10.5 per cent.Kiwibank increased its lending by six per cent in the half year to NZ$12.1 billion, while customer deposits rose five per cent, to NZ$12.3 billion. Kiwibank's lending growth was almost double system growth of 3.2 per cent.  However, its deposit growth of five per cent was below system growth, which was 8.2 per cent.Brock said Kiwibank's customer numbers were still growing and it had done slightly better than expected over the last six months from the fall-out resulting from the merger of ANZ and National bank customers. Kiwibank had a marketing plan known internally as 'Black Horse down' to capitalise on customers dissatisfied by the merger.Brock said significant numbers of both ANZ and National customers had switched accounts to Kiwibank, which, he said, now had 10 per cent of the market for personal banking customers. Brock didn't comment directly on the prospects for the Reserve Bank of New Zealand creating so-called macro-prudential tools, such as limits on loan-to-value ratios (LVRs), to cool an Auckland housing market the bank described as 'overheated' in a speech last week."I wouldn't call it an over-heated market," Brock said.Brock said Kiwibank had seen more high LVR lending in the market overall in the last year, but Kiwibank's General Disclosure Statement showed its own high LVR lending (over 80 per cent) had fallen NZ$27 million over the year to NZ$2.326 billion.