Fire and Emergency crews and staff from Envirowaste have made significant progress on the landfill fire at Hampton Downs, says a statement from Fire and Emergency New Zealand.

Incident controller Daryl Trim says ground crews, who have been working in arduous and often unpleasant conditions for the past three days, were to be stood down at the end of Tuesday.

"We're well on top of it so we're about to send the helicopters home and ground crews will be scaled right back," says Daryl.

"We'll only be working with heavy machinery today to finish putting on the clay cap to smother the fire completely."

The amount of smoke being produced by the fire has decreased significantly.

However, nearby residents should still heed the advice given earlier to stay indoors.

Anyone concerned about their health, especially those with respiratory conditions, should consult their doctor.

It's likely the operation to fully extinguish the fire will be complete within the next day or two.