Qantas Airways Ltd. Chief Executive Officer Vanessa Hudson is ramping up pressure on struggling Air New Zealand Ltd., adding close to 1 million seats on trans-Tasman routes to squeeze the ailing rival.

Both airlines are grappling with soaring fuel costs stemming from the Iran war, forcing flight cuts and higher fares. But Qantas, buoyed by record profits, is pouring capacity into New Zealand to grab market share in the struggling carrier’s backyard. Australia is New Zealand’s largest source of international visitors.