National's Chris Bishop tweeted he had been trying to lead the way on the Finance and Expenditure Select Committee: "join me!" and proposed a "unity ticket."
Asked about it this week both backed off a bit, possibly wary of buying into a trivial distraction so close to an election.
The Speaker's Rules for Parliament require "business attire" for both men and women and most Speakers have interpreted that to mean ties and jackets for men, although the jackets are sometimes dispensed of on hot summer days if the airconditioning is down.
Speaker David Carter said he was not aware of any widespread calls for change among MPs.
"I am personally in favour of the current standard of jacket and tie for men. I would not make a change without consulting Members"
Labour's Trevor Mallard, who hopes to be Speaker if Labour is in Government, believed it was inevitable at some point.
"My view, as someone who has never, ever learned to tie a tie, is that it's time for the change to occur."
Mallard said there would have to be consultation before a Speaker could make such a move.
"Modern business attire is changing and it's changing generationally. It is inevitable it will happen at some time."
Robertson said he agreed with the need to consult first.
"But most business meetings I go to, men are not wearing ties. And I think it's possible to be smart and business-like and not wear a tie. It's a personal view. I don't regard this as a major matter, it came up because of the House of Commons."
Bishop said he often went without a tie at the Finance and Expenditure Select Committee, as chair.
"I think you should wear ties in the Chamber because there's a formality and respect for the Parliament in there. But I'm less convinced about select committee, so I frequently try and go sans [without] tie on the committee. That's a controversial step to take for a first-term backbencher."
"I can understand the need for it in the House, but in most business environments these days, I would say a tie is probably a bit unusual. But these go in swings and roundabouts ... fashion trends come and go."
He declined to comment on the less restrictive rules for women in Parliament, saying there were many double standards that cut the other way.
Labour's Kris Faafoi said while he was getting sick of wearing ties, he also believed they were appropriate for the debating chamber.
Other dress code rules ban items which "advertise" a sports team. Hats are allowed, provided they do not have an advertising brand on them.
The same dress code applies for journalists sitting in the Press Gallery.