March 5 (Reuters) - The head of New Zealand's central bank resigned suddenly on Wednesday, ending a seven-year term that had become contentious at times after painfully high interest rates tipped the country into its worst downturn since 1991.

No reason was given for the surprise departure of Adrian Orr as governor of the Reserve Bank of New Zealand, whose term will now end three years early, on March 31.

"I leave the role with consumer price inflation at target, and an economy in a cyclical recovery following the long period of COVID-related disruption. The financial system remains sound," Orr said in a statement.

The current National Party-led government of Prime Minister Christopher Luxon was critical of Orr's stewardship while it was in opposition, blaming him for allowing inflation to soar after the pandemic and then for the high interest rates that led to recession.

Finance Minister Nicola Willis told reporters she had known for a few days that talks had been going on between Orr and the RBNZ board on him leaving, but offered no reason for the move.

Deputy Governor Christian Hawkesby will be the acting governor until March 31, when Willis - on the recommendation of the RBNZ board - will appoint a stand-in governor for up to six months as the central bank seeks a permanent replacement.