Under the Electoral Act, it is an offence - punishable by a fine of up to $20,000 - to influence electors on polling day.
Mr Lloyd Jenkins said as a result of the advice from the commission, the launch date for the exhibition had been changed to the next Saturday, September 27.
Napier Mayor Bill Dalton said he was not aware of the issue around the launch date or any concern the exhibition could be seen to influence voters on election day.
"It certainly seems extreme to me but if it's the law, it's the law and we're not about to start breaking the law."
Mrs Tirikatene-Sullivan broke ground in a number of areas during her time as new Zealand's longest-serving female Member of Parliament.
In 1970, she was the first sitting MP to give birth and, in 1972, she became the first Maori woman Cabinet minister.
The Southern Maori electorate she represented included Hawke's Bay and stretched from Gisborne, down the east coast of the North Island and included all of the South Island.
Mrs Tirikatene-Sullivan died in 2011.
She was known for her stylish, high-impact wardrobe and Mr Lloyd Jenkins described her as "the only New Zealander who you can immediately identify thorough her clothes".
The exhibition, currently in a storage area of the MTG, yesterday attracted a visit from Auckland-based Labour MP Jacinda Ardern who was in Napier campaigning alongside local candidate Stuart Nash.
"As a woman in Parliament, you're always interested in those who have gone before you and, at that time, there were so few women in Parliament," said Ms Ardern, who is Labour's arts, culture and heritage spokeswoman.
"I imagine the scrutiny on what you wore at that time was as intense, or even more so, than it is now. So I admire that she was able to take a position on how she chose to present herself, and retain that," she said.
"It was a very difficult time for any woman to be in politics so I have an affinity for all women MPs of that era regardless of the side of the house they were on."