New Zealand banks can't lift their retail deposits much further despite offering significantly higher interest rates, according to Westpac chief economist Brendan O'Donovan and senior economist Dominick Stephens.

Electricity generator and retailer TrustPower's up to $100 million senior bond offer provides investors with the opportunity to lock in a relatively high interest rate for seven years in an environment in which longer-term interest rates have been falling steadily.

Mortgage holders can be reasonably confident floating rates are unlikely to rise for some months after Reserve Bank governor Alan Bollard left interest rates unchanged.

ASB Bank's mortgage book actually shrank in the three months ended June 30 although its June quarter profitability soared.

Reserve Bank governor Alan Bollard is likely to leave interest rates unchanged next week amid the faltering economic recovery and the likely hit to confidence from the Canterbury earthquakes and South Canterbury Finance's collapse.

Investors wondering what to do with their about $1.73 billion in South Canterbury Finance and Allied Nationwide Finance refunds don't have to settle for bank deposit rates.

SBS Bank took a hit in the June quarter after deciding not to pass on rising wholesale interest rates to its customers.

ANZ Bank's share of the mortgage market continued to slide in the June quarter although its profitability improved markedly as a result of lower charges for bad loans.

TSB Bank grew its share of the mortgage market slightly in the June quarter but net profit fell sharply due to factors such as interest expense growing faster than interest income and tax changes.

Bank of New Zealand's mortgage book in the June quarter grew at its fastest pace since the June quarter of 2009 despite the overall mortgage market being particularly slow.

Westpac continued to grow its mortgage book aggressively in the June quarter and its profitability jumped sharply on much lower charges for bad loans.

Kiwibank continues to grow its mortgage book at a much faster pace than its market share but its momentum continues to wane.

While floating rate mortgages will rise again thanks to Reserve Bank governor Alan Bollard, the good news is they probably won't rise as much or as fast as previously expected.

Reserve Bank governor Alan Bollard will probably raise interest rates next week, despite recent data, particularly on the housing market, retail spending and inflation, being softer than expected.

Net new lending on mortgages by banks is slowing markedly with three of the big four banks punching well below their weight, their general disclosure statements show.

Reserve Bank governor Alan Bollard raised interest rates as expected, ensuring floating mortgage rates are on the way up.