Bay of Plenty Regional Council oil spill response staff have been working to contain an oil spill at Sulphur Point in Tauranga.

An estimated 2000 litres of oily sludge is believed to have been discharged from a tanker truck at around 5pm on Monday, as it was removing the sludge from a vessel. Some of this sludge has entered the water.

Regional Council staff deployed booms and other spill equipment to contain the spill as much as possible.

For safety reasons, clean-up activities were halted overnight but will recommence at first light.

Regional On Scene Commander Adrian Heays says while it appears most of the oil has been contained underneath the wharf, staff won't know until first light whether any has managed to get past the booms and further into the harbour.

Staff had been at the scene earlier in the day when a smaller spill had occurred involving the same vessel and tanker truck.

It's believed around 60 litres was spilled as part of this earlier event, with around 10 - 20 litres having entered the water. The cause of the incidents is not thought to be related.

A full investigation has commenced for both incidents.

"We expect to provide an update before 10am tomorrow morning once staff have had an opportunity to assess the situation and plan their action for the day.

"Staff have full PPE gear to use and are working with appropriate distancing due to COVID-19.

"While the public should not be out and about due to COVID-19, they are especially being asked to stay away from the area to avoid inadvertently causing any extra complications."