New Zealand is pushing ahead with plans for macro-prudential tools that could impose limits on loan-to-valuation ratios for mortgages.Finance Minister Bill English said in his first major speech of the year that he expected to sign a memorandum of understanding with the Reserve Bank of New Zealand on the framework for using the tools by the middle of the year.This is the first concrete timeframe for when the tools could be ready to use, as the Reserve Bank has previously said it would only begin consultation in March. Pressure is building on the Reserve Bank and the Government as house price inflation surges in Auckland and Christchurch, and a fresh bout of competitive activity between banks drives high LVR lending significantly higher.Late last year, and earlier this year, both new Reserve Bank Governor Graeme Wheeler and Prime Minister John Key said there was no rush to create or use the tools, but English's comments have increased the level of urgency."Over the next several weeks, the Reserve Bank will consult on its proposals to use more tools to help ensure financial stability. They will not be the answer to all problems created by excessive credit cycles. But they will certainly help at the margins," English said.The proposals could include forcing banks to hold a counter-cyclical credit buffer; higher risk weightings for capital requirements for certain types of loans; tougher funding rules; and limits on LVRs for mortgages."In particular, we want to avoid a strong upswing in asset values and any unsustainable growth in borrowing well in excess of economic growth," English said.Decisions about loan-to-value ratios and bank funding, and capital requirements should also be made by the independent Reserve Bank, he said."The temptation for some politicians to fiddle with the economy for short-term gain at the expense of long-term pain would be too great," he said.English noted there are some expectations that these tools will be used immediately to dampen the Auckland housing market. However, "those decisions will be in the hands of the Reserve Bank," he said.