When a deadly earthquake rocked Nepal in April, China and India rushed to send relief supplies and search-and-rescue teams. But when another humanitarian crisis — boats bearing thousands of migrants — appeared off Southeast Asian shores a month later, Asia’s two most-populous countries said and did little. Instead, offers to resettle the migrants came from Gambia and the United States.

The wealthiest nations in the Asia-Pacific region stood back as well. Australia declared it would not resettle the migrants, mostly Muslim Rohingya who boarded rickety vessels fleeing religious persecution in Myanmar or poor Bangladeshis seeking jobs. Japan pledged $3.5 million in emergency assistance but also refrained from offering to take any in.

More than a month after Malaysia and Indonesia agreed to provide temporary shelter for up to 7,000 of the migrants stranded at sea, there has been no sign of progress in finding them a permanent home, nor any hint that Myanmar will address the conditions driving the Rohingya exodus. Yet Asia’s most powerful nations are essentially sitting out the crisis.

… ‘‘The domestic priority is internal stability,’’ said Alistair D. B. Cook, a research fellow with the S. Rajaratnam School of International Studies at Nanyang Technological University in Singapore.

Mr. Cook said a historic emphasis on non-interference in Asia has meant that the only countries in the region that have responded to the migration crisis are those that had migrants leave or come ashore. ‘‘Essentially what we see now, we see going as far back as the Indochinese exodus,’’ he said. ‘‘How states responded then and how they respond now, there hasn’t been too much change.’’