An estimated six tonnes of rubbish was taken from the bottom of Wellington's harbour yesterday, including more than 2000 bottles and live ammunition.

Ghost Diving NZ held a volunteer day in the marina in effort to reoxygenate the seafloor which is carpeted with rubbish.

The group's founder Rob Wilson says four e-scooters, an aircraft tyre, car batteries and shopping trolleys were all hauled out of the ocean.

Wilson says it was encouraging to find seaweed growing in patches for the first time after volunteering in the area for six years.