The Springvale Structure Plan, commissioned in 2012, sets out the expansion and once finalised it will be put into the district plan.
"This isn't set in stone and it is definitely open to change," Edmonds said.
Council is hosting two information sessions on June 12 and 13 from 4.30pm at the Wanganui Golf Club.
Whanganui mayor Hamish McDouall said the plan would give a substantial increase in the number of properties available for development in the Whanganui urban area.
"Springvale has developed from a few farms houses in the 1950s to a very desirable suburb and this has the potential to open a lot of land for that development."
Sustainable development was the key, he said.
"I absolutely agree that Mosston Rd should be the boundary for it.
"You need a limit because otherwise we'll be pushing the urban boundary further and further and causing infrastructure stretch. Just look at Auckland, look at Palmerston North.
"This along with the intensification within the city boundary... really offers what people are wanting and that places to live in Whanganui.
Councillors Alan Taylor and Rob Vinsen expressed support for the plan.
"I think as long as I've been on the council I've never seen this much land - potential for 575 sections - plus what we've got on Great North Rd and I think it bodes well for the future," Vinsen said.
Council is also planning to rezone 58ha around Otamatea West from rural to residential to cater for 630 new houses which could be needed in the area by 2065.
The process has paused in March while commissioners sought adequate consultation with iwi.
For more information visit www.whanganui.govt.nz/springvale-structure-plan
