Home loan borrowers look set to face higher fixed-term mortgage rates despite a predicted cut to the official cash rate this week.

Economists are widely expecting the Reserve Bank governor to cut the OCR by another 25 basis points to a record low 1.75 per cent on Thursday.

But experts say that won't bring fixed term mortgage rates down and instead they are likely to head upwards on the back of rising international borrowing costs for the banks.

ASB increased the fixed-term rates for its three and five year mortgages on Friday and other banks are expected to follow suit.

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David Tripe, a banking expert with Massey University, said it was no surprise ASB had moved to increase rates as the swap rates - the rates at which bank's borrow on the money market - had jumped significantly in the last three months.

On August 15 the five year swap rate was 2.08 per cent while on Monday last week it was 2.42 per cent, he said.

The three-year swap rate had risen from 1.98 per cent to 2.23 per cent over the same time.

ASB increased its three-year standard fixed term rate from 4.89 per cent to 5.09 per cent and lifted its five-year standard rate from 5.29 per cent to 5.49 per cent.

Tripe said some of the other major banks may also move this week.

"I wouldn't be surprised," he said.

Banks are having to borrow more money on the international market as the growth in local deposits has failed to keep pace with the demand for housing loans.

Instead of putting their money in the bank, savers have ploughed it into the booming property market.

That has left the banks scrambling to attract more deposits.

After the last official cash rate cut in August many of the major banks passed just 5 basis points on to floating rate mortgage holders, choosing instead to increase deposit rates.

The move is good news for savers who have faced years of low interest rates.

Karen Tatterson, a mortgage broker with Loan Market in Auckland, said she expected banks to take a similar tack with this week's cut.

"I think they will do the same as last time - increase deposit rates to try and pull some money in."

She doubted it would make a huge difference for savers but said it may attract some money back from people who had invested with finance companies to get a better rate and now wanted to lower their risk.

Tatterson said mortgage holders should not panic about the increasing rates as they would still be at historical lows.

"If you are worried fix for a longer term. Consider your options and get good sound advice. If you are looking to stay in a property for a long time take a longer term rate."