General information for preparation, not a lending decision.帮助您准备问题的一般信息，不是贷款决定。
Interest-only vs principal + interest只还利息 vs 本息同还
When financing an investment property, you can choose between interest-only (IO) repayments or principal-and-interest (P&I) repayments. Each structure affects your cashflow, tax position, and long-term equity differently.
Interest-only loans require you to pay only the interest charged each month: the loan balance stays the same. For example, a $400,000 investment loan at 6.5% would cost roughly $2,167 per month in interest under an IO arrangement. The same loan on P&I over 30 years would cost approximately $2,528 per month, with the difference reducing the principal.
The primary advantage of IO is improved cashflow. Lower monthly repayments can make it easier to hold a negatively geared property: where rental income does not fully cover the mortgage: without stressing your personal finances. The interest payments on an investment property loan are generally tax-deductible in New Zealand, while the principal portion is not. An IO structure maximises the deductible portion of each repayment.
Most lenders in New Zealand offer IO terms of one to five years on investment properties. After the IO period expires, the loan automatically converts to P&I unless you apply for an extension. Extensions are not guaranteed: the lender will reassess your serviceability at that point.
The trade-off is that you build no equity through repayments during the IO period. If property values plateau or decline, your LVR may not improve. Some lenders also charge a slightly higher interest rate on IO loans: typically 0.1% to 0.3% above their standard P&I rate: and may restrict IO availability on high-LVR loans (above 70% LVR for investment properties under current Reserve Bank rules).
Principal-and-interest repayments gradually reduce the debt. Over a 30-year term on a $400,000 loan at 6.5%, the total interest paid under P&I is roughly $510,000 compared to $780,000 under a permanent IO scenario: though few investors keep one loan on IO for 30 years. The equity built through P&I can also support future borrowing, such as a deposit on another investment property.
The choice often depends on your investment strategy. Investors with a long-term hold strategy and stable rental income may prefer P&I for disciplined equity building. Those focused on cashflow preservation, particularly in a rising-rate environment or on a highly leveraged portfolio, may prefer IO with a plan to convert to P&I when the cashflow allows.
The mixed-strategy approach is common: keep an existing investment property on P&I while taking a new investment on IO, or rotate between IO periods and P&I periods as market conditions change.
A mortgage adviser can model the after-tax cashflow difference between IO and P&I using your actual rental income, interest rate, and marginal tax rate.
在为投资房贷款融资时，您可以选择只还利息（IO）或本息同还（P&I）的还款方式。每种结构对现金流、税务状况和长期净值的积累都有不同的影响。
只还利息贷款要求您每月只还利息: 贷款余额保持不变。例如，一笔40万纽币的投资房贷款，利率6.5%，在IO安排下每月利息约为2,167纽币。同样的贷款在30年P&I下每月约2,528纽币，多出的部分用于减少本金。
IO的主要优势是改善现金流。较低的月供让您更容易持有一处负杠杆房产: 即租金收入不足以完全覆盖按揭贷款: 而不会给个人财务带来压力。投资房贷款的利息在新西兰通常可以抵税，而本金部分则不能。IO结构使得每笔还款中的可抵税部分最大化。
新西兰大多数贷款机构为投资房提供1至5年的IO期限。IO期结束后，贷款会自动转为P&I，除非您申请延期。延期并不保证获批: 贷款机构届时会重新评估您的还款能力。
IO的代价是您在IO期间通过还款积累不了任何净值。如果房价持平或下跌，您的LVR可能不会改善。一些贷款机构对IO贷款收取略高的利率: 通常比标准P&I利率高出0.1%到0.3%: 并且可能在高LVR贷款（目前储备银行规则下投资房超过70% LVR）中限制IO的使用。
本息同还逐步减少债务。以30年期40万纽币贷款、利率6.5%计算，P&I下总利息约为51万纽币，而永久IO场景下约为78万纽币: 不过很少有投资者会保持同一笔贷款IO状态30年。通过P&I累积的净值还可以支持未来的借款，例如用于另一套投资房的首付。
选择通常取决于您的投资策略。采用长期持有策略且租金收入稳定的投资者，可能更倾向于P&I以获得纪律性的净值积累。而专注于保护现金流的投资者，尤其是在利率上升环境或高杠杆组合中，可能更偏好IO，并计划在现金流允许时转为P&I。
混合策略很常见：将现有投资房保持只还利息，同时将额外还款用于自住房贷款（其利息不可抵税）。这样可以更快减少不可抵税债务，同时保持投资房的现金流可控。一些贷款机构对同一组合中IO房产的数量有上限，因此在决定长期IO策略前值得确认贷款机构的政策。
贷款顾问可以根据您的具体税率等级、房产价值和贷款金额，模拟IO与P&I之间的税后现金流差异。正确的选择取决于您的现金流需求、税务状况和长期净值目标。
Points to keep in mind需要留意的事项
- Read the details alongside your own figures, timing, and documents.请结合自己的数字、时间安排和材料阅读这些内容。
- Use this article to prepare questions. Current lender criteria and personal circumstances still need to be checked.把文章当作准备问题的起点，具体贷款机构政策和个人情况仍需进一步确认。
Questions people often ask常见问题
No. This is general information from an existing service-page article. Approval, eligibility, cost, and suitability depend on your circumstances and the relevant lender criteria.
不能。这是从现有服务页面整理的一般信息。资格、审批、成本和适合性仍取决于您的实际情况以及相关贷款机构的评估标准。
Use it to identify the questions and documents that matter to your situation before deciding whether to start a conversation.
您可以把它作为整理问题和准备材料的起点，再决定是否需要结合自己的情况进一步沟通。
Source context来源背景
These public sources provide context for the general information in this article.以下公开来源为本文的一般信息提供背景。