The Reserve Bank of New Zealand has tightened monetary policy for the fourth time in five months, lifting its Official Cash Rate 25 basis points to 3.5 per cent, its highest point since January 2009. The RBNZ also signalled a pause in its hiking cycle that economists said could last well into 2015.The central bank also jawboned the currency lower in a way that economists said suggested currency intervention could be launched within days.Citing an encouraging adjustment by the economy since it started tightening in March, the Reserve Bank said wage inflation remained moderate and house price inflation had continued to moderate. The central bank stopped short of saying interest rates were on hold, saying the economy continued to grow faster than its potential but it wanted time to assess the impact of the increase in the OCR from 2.5 per cent to 3.5 per cent."It is prudent that there now be a period of assessment before interest rates adjust further towards a more neutral level," Governor Graeme Wheeler said in a seven-paragraph statement issued with the OCR decision."The speed and extent to which the OCR will need to rise will depend on the assessment of the impact of the tightening in monetary policy to date, and the implications of future economic and financial data for inflationary pressures," Wheeler said.The bank has previously estimated the neutral rate at around 4.5 per cent and it forecast in its full June Monetary Policy Statement that the OCR would rise to that level by late 2015. Economists said the bank was now likely to wait until its December 11 decision at the earliest before resuming hiking. Some expected the bank would wait until March next year.Meanwhile, the Reserve Bank also issued a strong warning about the strength of the New Zealand dollar, which remains high despite sharp falls in the last six months in commodity prices. The New Zealand dollar rose 7 per cent in the first half of 2014, despite a 30 to 40 per cent fall dairy and log prices."With the exchange rate yet to adjust to weakening commodity prices, the level of the New Zealand dollar is unjustified and unsustainable and there is potential for a significant fall," Wheeler said.The New Zealand dollar fell more than 1 USc on Thursday after the statement, closing at US$0.857.