Ma'a Nonu's decision to leave the Blues for the Highlanders has caused more than just a minor stir in New Zealand.

New Blues coach John Kirwan said he felt the All Black veteran went back on a handshake agreement, while Blues CEO Andy Dalton wants the New Zealand Rugby Union to urgently address the current Super Rugby contracting process.

The fall-out follows Nonu's decision not honour his two-year deal with the Blues.

Dalton told the New Zealand media the NZRU has assured them that it has the legal rights to tear up a Super Rugby contract.

He says the integrity of the franchise contracting process needs to be changed.

"Any two year deal is just not worth the paper that it's written on if that is the case, I'll be very surprised if there's not some changes to the contract process," Dalton said.

He says their contract with Nonu meant nothing to the NZRU.

"The contract with the NZRU, Ma'a and the Blues was terminated and a new contract with the NZRU and the Highlanders was drafted up."

An expressive Kirwan was a lot more forthright in his reaction.

"Frustrated? No!" Kirwan said, adding: "Disappointed? Yes!"

He described as "an average 24 hours" the lead-up to Nonu's announcement on Tuesday that he will move south.

"I am disappointed in him, disappointed in the process," Kirwan said.

"However, in a weird sort of way [I am] happy, as it is time to move on."

He described it as "exciting" at the same time.

"I slept like a baby last night, because we are going to have a young and exciting team.

"It has been a testing 24 hours, but actually I am good with it. One of the most disappointing things was, we thought Ma'a was coming, so we made some pretty strong, hard decisions that might have changed if we had know a little bit earlier.

"It is just the nature of the beast working here in New Zealand - it is more of a contractual, structural issue that is not right."

Kirwan said the issue with Nonu is that he indicated that he was staying with the Blues, but then made a sudden about turn.

"I feel pretty let down," Kirwan said, adding: "The down side of that is that we could have signed, or done things differently.

"I feel as if the franchise has been exposed, and I am disappointed.

"I've said all along I would have loved to have coached Ma'a, but he's not here and it is going to be his loss.

"We have to move on - it is another man's opportunity and I am really excited, but it just changes the way our team is going to look. We'll be very young and exciting and that will come with its pros and its cons.

"I want people who really love this town [sic], this region, this jersey.

"This is my home and I am not going to let anyone stand in my way or our way to make sure this is about the jersey and about our franchise."