Jim Fitzpatrick MP has called John McDonnell's comment on the Grenfell Tower victims "inappropriate".
Samples from 60 buildings in 25 local authorities have failed the fire-safety tests which were ordered in the wake of the blaze in west London.
Over the weekend, McDonnell - Labour's shadow chancellor - said the victims of the fire, of whom 79 have been confirmed either dead or missing, were "murdered" by "political decisions".
Jim Fitzpatrick, the Labour MP for Poplar and Limehouse and a former firefighter, said this was "unhelpful" in an interview with Julia Hartley-Brewer.
He said: "Clearly, there have been catastrophic failures.
"These failures have not just come from the building and fire protection itself, but outside as well.
"I don’t think he’s [John McDonnell] right. To jump to conclusions at this time is unhelpful and completely inappropriate."