The forces include large falls in commodity prices, especially dairy and oil, low international interest rates and record net immigration levels.
New Zealand's monetary policy framework was flexible and was supporting the economy's adjustment to those significant external forces, he wrote in the central bank's annual report.
The bank used macro-prudential instruments to manage the systemic risks that could develop during boom-bust financial cycles, he said.
''We provide currency to meet the public's cash needs, we set prudential requirements for banks, other financial institutions and insurance companies and we provide services to allow financial institutions to settle payments between one another.''
The Reserve Bank and Finance Minister Bill English earlier negotiated a new five-year funding agreement for 2015-20.
The Wellington-based central bank reported a profit of $624million for the 12 months ended June 30, up from a profit of $56million a year earlier, according to figures in annual report.
Net investment revenue soared almost seven-fold to $681million in the year, including a $379million gain from foreign exchange positions, compared to a loss of $198million in 2015.
The gain on currency trading means the Reserve Bank lifted its distribution to the government to $510million from a more modest $20million return in 2014.
The central bank sold a net $554million of New Zealand dollars in the 12 months ended June 30, a period when the trade-weighted index dropped 12.3% and covering a period when it intervened in FX markets, selling currency to try and push it lower.
It was the biggest return to the government since 2009, when the central bank paid $630million, its first year under a new dividend policy that included foreign exchange gains when calculating the distribution, and a period when the TWI dropped 10.2% and the Reserve Bank was a net buyer of $1.27billion.
The bank's open foreign currency position was $3.5billion as at June 30, up $1billion from a year earlier, which it said reflected a combination of foreign currency purchases and depreciation of the New Zealand dollar.
Mr Wheeler said the bank faced a tight budgetary framework under its new five-year funding agreement that started from July 1, and had made a net 15 staff redundant earlier this year to help prepare for the constraints.
The bank's total operating expenses rose to $70.6million in the year from $60.5million in 2014, including a $6.7million provision for its old bank notes, and $1million of restructuring costs.
At a glance
• Net profit $624 million.
• Dividend of $510 million paid to Government.
• Tight budgetary restraints loom in future.
• Fifteen staff made redundant to prepare for tighter conditions.
