Ocado couriers have pointed the finger at the retailer for a “huge crash” that happened outside its warehouse.
A van from its rapid delivery service, Zoom, crashed into a bus on Friday as it left the Acton depot.
It comes after claims that Ocado – which subcontracted Zoom until recently – was understaffed after not bringing a number of workers “in-house”.
The FTSE 100 group denies this and said all couriers would be “offered the opportunity” to stay on.
“New drivers… are being pushed to the limit and struggling to meet demand,” a group of employees wrote on Twitter.
“Ocado are responsible for dangerous accidents like this.”
The van appeared to be a Highway Maintenance vehicle, prompting claims that Ocado was relying on “big vans from other sites” because it was “struggling with no workers”.
In a statement, the online supermarket said: “We’re thoroughly investigating the cause of this incident but are pleased no-one was injured.
“We recently leased new vehicles for our Zoom site and are awaiting the branding change for this particular van.”
Zoom has been forced to expand its vehicle fleet after Ocado ditched a controversial subcontractor this autumn.
Staff had been allowed to make deliveries in their own vehicles when working for Ryde, but this is no longer the case.
Despite the Highway Maintenance branding, the van is not thought to have been recently used as a service vehicle.