Powerhouse state body Swimming Queensland (SQ) says it refused to support a range of reforms to Swimming Australia (SA) last week because it believes the changes make the board of the national body less accountable.
SQ was the only vote in an eight-one split to stand against the new constitution, ratified at a Special General Meeting last Friday.
SA averted a takeover by the sport's global governing body World Aquatics, known as AQUA, by voting for reform at the crisis meeting.
After a string of presidents and chief executives at SA in recent years, AQUA threatened expulsion if SA didn't move to a centralised governance system instead of a model in which states and territories held the balance of power.
Under the changes, effective immediately, an athletes' commission will be created and empowered to nominate a candidate to the SA board.
The number of voting members will be increased from nine to more than 20.
SQ boss Kevin Hasemann issued a statement on Monday explaining his state's position and said the changes risked marginalising grass-roots swimming.
"Too great a proportion of appointed directors can easily result in a board no longer being representative of active participants in the sport or activity," Hasemann said.
"It's hard to see what benefit grassroots swimming will derive from this new structure.
"A further concern is that some crucial details of the constitutional reform are missing, such as an increase in the number of people who can vote at general meetings and in board elections, and the creation and role of an athletes' commission."
Hasemann questioned the timing of the demand by AQUA, saying there were no current claims of mismanagement.
