The development off Swansea Road would include up to 1,950 houses and flats, a primary school, pub, sports pitches and play areas.
But Llangyfelach community council said access via two new junctions from Swansea Road and Penplas Road would cause traffic “chaos”.
The outline plans are expected to be approved by Swansea councillors on 8 January.
A road would run through the development, connecting the two junctions.
Llangyfelach councillor Gareth Sullivan said: “At peak times there is a considerable tailback at the moment… It could mean Llangyfelach is a ‘no-go’ area.”
He added he was worried about the cumulative impact of this site and other planned builds and argued the northern access could be via the A48 instead.
About 290 of the properties would be classed as affordable housing, with about half of the 115-hectare site built on and the remainder used mainly for open spaces.
A report to councillors said housing land was in short supply in Swansea, and the site in question was earmarked for new housing, estimating the population of the new development could be up to 4,680 people.
The Welsh Government said the development’s impact on junction 46 of the M4 would be “minimal”.
The site is the largest of six “strategic development areas” in Swansea’s new local development plan, which is close to being finalised.