Two of New Zealand's largest media companies could find out today whether their appeal against the rejection of their merger bid has been successful.

Today is the final day of NZME and Fairfax's 10-day hearing in Wellington, where they appealed against the Commerce Commision's decision to disallow a proposed merger.

The Commision said in May that the proposed deal was clearly in response to a "challenging environment" for media, "as they seek to transition from their traditional print products to a sustainable online model".