New Zealand shares fell on Friday as markets remain concerned about the ongoing Middle East conflict, which poses a threat to global oil supply and raises inflation concerns.

The S&P/NZX 50 fell 0.7% or 98.5 points to close at 13,519.35.

"The range of plausible outcomes (of ​the war) has expanded to include both the possibility of an exceptionally constructive resolution and a highly destructive one," said Daleep Singh, ⁠chief global economist at PGIM Fixed Income, as quoted by Reuters.

"What matters now is whether the war will last days, weeks, or longer," said Marco Oviedo, senior strategist at XP Investimentos, as quoted by Bloomberg.

Oviedo said that the possibility of the conflict being a short one remains the base case, with the US on the winning side, but Iran's refusal to back down is keeping things tense.

On Wednesday, the S&P 500 rose 0.8%, the Nasdaq gained 1.29%, and the Dow Jones added 0.49%.

In domestic news, spending on Westpac-issued debit and credit cards in New Zealand rose 0.7% in February after adjusting for normal seasonal variations, with spending levels now up 6.6% compared with the same time last year, according to a report by the bank.

In corporate news, Westpac Banking (NZE:WBC, ASX:WBC) said it intends to voluntarily deregister from the US Securities and Exchange Commission (SEC) as early as May to terminate its US SEC reporting obligations.

SkyCity Entertainment Group (NZE:SKC, ASX:SKC) said legal proceedings have been filed against the company, SkyCity Auckland Holdings, and Malta-based Silvereye Entertainment over the legality of online gaming operations run by Silvereye for the SkyCity Online platform.