Most economists are picking March inflation to be 0.4% for the three months and 1% annually, below the Reserve Bank's forecasts.
Inflation was 1.9% in September and 1.6% in December.
Recent business surveys were consistent with the BNZ view New Zealand's economic growth slowed through the second half of last year and into the first half of this year, he said.
''One thing that won't derail the expansion any time soon is an over-zealous central bank tightening the reins.
''In fact, we think this week's inflation data will leave the Reserve Bank feeling very smug its lack of intent to raise interest rates for a considerable further period of time is well-justified.''
There was a ''very real risk'' headline inflation would again surprise the Reserve Bank to the downside, Mr Toplis said.
When the February monetary policy statement was released, the central bank projected March quarter CPI inflation would be 0.6%, delivering an annual reading of 1.1%.
The BNZ was projecting 0.4% and 1% respectively.
The Reserve Bank's published forecasts appeared to be impossible, in a purely technical sense, he said.
From what the BNZ could see, if the 0.6% result the Reserve Bank projected eventuated, the annual number would be 1.2%, not 1.1%.
Even if the CPI did go higher than expected, the annual reading would still be well shy of the Reserve Bank's 2% target band mid-point and it would be unlikely to shift the Reserve Bank to a more hawkish stance, Mr Toplis said.
ASB chief economist Nick Tuffley said the key drivers of inflation for the three months ended March were expected to come from higher tobacco prices, higher rent costs and a further lift in housing construction costs.
Higher tobacco costs reflected another round of the Government's four-year annual 10% excise tax which, was announced in Budget 2016.
Rent costs were also expected to have lifted as they tended to reach a seasonal peak in the first quarter, in line with the start of the school and university year, he said.
This year, rent costs appeared to be particularly high in centres like Wellington as a shortage of rental properties lifted prices.
Construction costs were also expected to keep rising as capacity constraints in the construction sector continued to push prices higher.
Construction costs in the CPI, which represented the cost of building a new home excluding the land, were running at more than 5% a year, far higher than December's 1.6% headline CPI inflation, Mr Tuffley said.
Meanwhile, the Reserve Bank of Australia's board said the next interest rate move was likely to be a hike.
However, with a fall in unemployment and increase in inflation only occurring gradually, the board members also agreed there was not a strong case for a rate hike in the near-future, according to the minutes of RBA's April 3 board meeting, released yesterday.
