The visit would have been Mr Abbott's first chance to meet Pacific leaders since the election of his coalition government in September last year to discuss many regionally important issues.
However, with the downing of Malaysian Airlines flight MH17 in the Ukraine and other pressing matters Mr Abbott has decided the trip is not possible.
Deputy Prime Minister Warren Truss will instead lead the Australian delegation and Parliamentary Secretary Brett Mason.
The Lowy Institute's Vanuatu-based non-resident fellow, Dr Tess Newton Cain, told Pacific Beat it is a missed opportunity for the Australian Government.
"Prime Minister Abbott is dealing with a time of great national tragedy and trauma for Australia," she said.
"I think that is something the leaders of the region would recognise, and would be expecting to use the opportunity of the forum as a platform on which they could express their condolences to Prime Minister Abbott and Australia."
Dr Cain says it is unfortunate that for two years in a row the prime minister of Australia will not be present at the forum.
"This just leads ... to a sense that we're not seeing Prime Minister Abbott being able to take the opportunity to really deliver on the promise of a new, deeper and more nuanced engagement with the region, which we were given to expect while his government was in opposition and indeed since it came to power last year," she said.
Dr Cain says while Australia will be represented at the forum, Pacific leaders would have been looking for personal assurances from Mr Abbott on a number of key issues and relationships.