Norwegian Cruise Line Holdings Ltd., the world's third-largest cruise operator, is in advanced talks to acquire peer Prestige Cruises International Inc. for around $3 billion, according to people familiar with the matter.

A deal would give Norwegian Cruise, a company with a market value of $6.8 billion, access to Prestige Cruises' luxury cruise ships and affluent clientele as it competes with bigger rivals Royal Caribbean Cruises Ltd. and Carnival Corp.

An agreement may be announced as early as this week, the sources said on Sunday, cautioning that the talks could still fall apart. The owner of Prestige Cruises, private equity firm Apollo Global Management LLC, also owns a 20 percent stake in Norwegian Cruise.

The sources asked not to be identified because the negotiations are not public. Norwegian Cruise and Prestige Cruises representatives did not respond to requests for comment, while an Apollo spokesman declined to comment.