The redevelopment of Stuart Flats will generate a 240 per cent increase in traffic around the Griffith site, tender documents for an adjacent demolition have revealed.
However inner south Canberra residents say the modelling was not a complete picture and have renewed calls for a masterplan for Manuka.
The parcel of land on Light Street will be sold in 2018-19 as part of the federal asset recycling scheme, where governments get a bonus for selling off their ageing public assets.
The site allows for a mix of six-storey apartments and three-storey townhouses with a maximum of 492 homes.
Currently there are 29 bedsitter and 117 two-bedroom flats on the 30,137 square-metre site.
The government will start consulting with tenants about the sale from next month, an ACT government spokesman said, with all to be in their new homes by early 2019.
The former Menslink building across the road will be demolished, before being sold separately, but at the same time as Stuart Flats sale.
Tender documents for its demolition have shown the scale of traffic disruption expected from Stuart Flats redevelopment
A 2016 traffic report showed while the tenants of the flats currently undertook about 876 trips per day, the redeveloped site would generate 2952 trips per day.
The same analysis showed the site would also require a maximum 984 residential parking spaces and 123 visitor spaces.
And while it indicated the redevelopment would have a "minimal" impact on the performance of the five surrounding intersections, it warned the Canberra Avenue, Lefroy and Eyre Streets intersection already operated at capacity and the redevelopment would have an "adverse" impact.
Based on the ACT Road Hierarchy classification, Stuart Street was already over capacity under the existing scenario, while the remaining roads were within capacity.
But Griffith Narrabundah Community Council president Dr Leo Dobes said the modelling should be treated with caution, as its matrix did not include data about trip destinations.
However he said it was clear the trips taken around the site would vary considerably once it was redeveloped because of the higher density and changed socioeconomic status of new residents.
"The people who live there at the moment are on low incomes and they're going to have very different travel habits to people on higher incomes," Dr Dobes said.
Dr Dobes said a masterplan needed to be developed for Manuka as the "piecemeal" approach to approving developments threatened to choke the suburb centre.
"Planners come along and look at a development like Stuart Flats and say there's plenty of on-street parking, so developers are not forced to provide parking on site.
"Because they're doing it in a piecemeal way Manuka will end up like Kingston where there's no parking on the street. That'll kill Kingston eventually and it may end up killing Manuka."