Listener columnist Jane Clifton replied that it was a "fashion atrocity" but cautioned Ms Ardern to act carefully in case the MPs "over-atoned" by copying Sonny Bill Williams and taking off the offending tops.
Danyl McLauchlan suggested the vests showed that the MPs "represent vested interests?"
Grant Young suggested Labour link it to their working class roots and solidarity with the poor: "In these difficult economic conditions, ordinary people struggle to afford sleeves?"
Lew Stoddard took the philosophical approach, using it as a metaphor for the party: "Vests - for people who are too wimpy to stand the chill, but too conventional to just wear a damned jacket inside. Labour in a nutshell."
Another twitter user said the trio resembled the three stooges.
Ms Ardern later said she was not against vests, but was concerned about so many vests which were the same - and the potential that the men concerned would be mistaken for hotel staff, who wore similar vests.