Primary schoolchildren near the proposed WestConnex interchange at St Peters have been prevented from playing outside because of the power of the rotten egg smell that has repeatedly overwhelmed their neighbourhood.

Contractors working to turn a former tip into a vast motorway interchange have repeatedly stirred up odours so powerful the Sydney Motorway Corporation has advised nearby residents to stay inside with the windows shut.

Sarina Kilham says she keeps her five-year-old daughter home from school on "strong odour days". Credit:Louise Kennerley

And at the St Peters Primary School, two blocks from the construction site, teachers have twice kept children inside rather then letting them out for meals and play.

"On the strong odour days I no longer send my daughter to school," said Sarina Kilham, whose five-year-old daughter attends St Peters Primary.