It is understood Laulala, now playing for Irish club Munster, was given the all-clear by Kiwi coach Rob Penney to join the Chiefs on a short-term contract, but the deal failed to get past the NZRU.
While remaining diplomatic in public, the Chiefs - who are suffering a midfield injury crisis - are understood to be extremely frustrated by the NZRU's decision, which was apparently made because their request came after the April 1 cut-off.
However, the Highlanders signed former All Blacks' and Crusaders' No 8 Mose Tuiali'i from Japanese club rugby late this season. His first game for his new team was against the Blues at Eden Park on April 5 soon after he arrived.
There is a perception the Highlanders, who were on a eight-game losing streak this season before finally getting a victory against the Sharks in Dunedin, were being treated leniently, while the defending champion Chiefs have been left to fend for themselves.
NZRU general manager of professional rugby Neil Sorensen, understood to be on the panel who rejected the Chiefs' request, said in a statement: "Investec Super Rugby is primarily about players who commit to playing their rugby in New Zealand. While our priority is to contract players in New Zealand, teams can apply for exemptions.
"In this case, we did not think that it was prudent to have a player come in to play for a few weeks, and not be available to play in the finals. Sanzar also requires players to have played before 1 April in order to be eligible for finals matches. We do not want to open the door for players to consider short term contracts as a choice."
This suggests the Highlanders were looked at differently as they had no chance of making the finals.
Rennie told 3News after a Chiefs' training session yesterday: "We knew the rules going in. It was an appeal for some help, really."
He said the declining pool of players in New Zealand was becoming a real issue.
"We've got a lot of our next tier going overseas," he said.
"There's an enormous amount of players who have gone recently or are about to go. More than people realise, I think. When you look at that situation we're starting to look at guys who haven't even started for their NPC side."
Laulala, 31, who played two tests for the All Blacks between 2004-06, would have been a valuable addition to the Chiefs.
The Crusaders have struggled to find a replacement for his consistent midfield penetration since he left after the 2009 season, initially for the Cardiff Blues before signing with former Canterbury coach Penney at Munster.
He is also an excellent defender, a problem area for the Chiefs this season.
With Kahui ruled out for the rest of the season with another shoulder injury and Andrew Horrell recovering from a serious ankle sprain, the Chiefs have only the inexperienced Bundee Aki, Charlie Ngatai - who is recovering from a hamstring strain - and Save Tokula available in the midfield to play the Hurricanes in Wellington on Friday.
Tim Nanai-Williams is out until July after a spell in hospital with a stomach ulcer.