The shake-up followed a students' online referendum, which voted to reduce the executive from 17 to 10 positions.
Positions lost include the women's, "queer", postgraduate and Pacific Islands representatives, while the Te Roopu Maori president will become an ex-officio executive position.
OUSA president Harriet Geoghegan said the new structure would improve the executive's efficiency.
"We can have as many representatives on the executive as could be imagined, but if our internal structure isn't functioning efficiently then we would be doing them a disservice," she said yesterday.
"Under the current structure, it can be difficult for representatives to bring all issues of their constituents to a full executive meeting and this structure ensures all issues can be fully discussed by people best placed to make good recommendations.
"The representation structure will be strengthened next year by the establishment of eight committees - welfare, education, postgraduate, policy, finance and expenditure, recreation, communications and events."
Nominations for the 2011 executive opened yesterday and close at 4pm on Friday.
The positions are: president, administrative vice-president, finance and services officer, education officer, welfare officer and five general executive officers, with portfolios covering postgraduate, international, recreation, colleges and communications, and campaigns.
