South Korea's trade deficit with Japan has reduced since March 11 when the deadly earthquake hit Japan's northeastern region, Nomura International said Thursday.

"Since the Japanese earthquake, South Korea's trade deficit with Japan declined 26 percent during the March-April period from a year earlier," Kwon Young-sun, an economist at Nomura in Hong Kong, said in a report.

According the report, the nation's exports to Japan surged 58 percent on-year during the March-April period, with imports from Japan at a much slower rate of 6 percent.

Exports of petroleum and chemical products were particularly brisk over the cited period as Japan's petrochemical sector was crippled after the quake. Petroleum shipments to Japan skyrocketed 270 percent on-year between March and April, with chemical exports surging 54 percent.

Meanwhile, imports of machinery and transport equipment from Japan contracted 5.1 percent on-year over the same period largely due to the supply constraints and production cuts in Japan, according to Nomura.