Associate nations' outrage over exclusion from the 2015 World Cup might have prompted the ICC to reconsider its decision but co-hosts New Zealand's Board has backed the trimming, saying a 10-team format works best from the organisers' point of view.
New Zealand Cricket CEO Justin Vaughan said the ICC, which is set to review the decision in its next ICC executive board meeting, should decide quickly about the number of teams in the mega-event which they will host jointly along with Australia.
"Look, I am sympathetic to Ireland, in particular, and the way they have performed at world events," Vaughan told the 'Sunday Star-Times'.
"A ten-team competition works far better from a host perspective than a 12-team competition does. A 12-team competition would necessitate the introduction of a Super Sixes stage in between two pools of six and an elimination round.
"The problem with the Super Six portion of a competition is that there's no certainty around who is playing whom and where. To sell tickets and organise international tour groups or international visitors becomes hugely problematic when you've got a section of the tournament where you don't know who is playing where," he added.
Vaughan said the 2015 edition would soon have a CEO and the ICC should make the number of teams for the event clear as quickly as possible.
"From an event host perspective, it's very unhelpful to have uncertainty with regard to what the format of the competition is going to look like," he said.
"We are in the process of looking for a CEO but how do you set up an organisation if you don't even know how many teams are going to participate in it?
"As the hosts of that competition, it is unhelpful to have renewed uncertainty over the format," he added.