Media playback is unsupported on your device Media caption Footage from the US Air Force shows the fishing boat stranded in heavy sea ice

A New Zealand plane has dropped supplies of equipment and fuel to a Russian fishing boat stranded in icy Antarctic waters.

A water pump and containers of diesel were dropped onto the ice next to the vessel which is about 2,000 nautical miles (3,700km) south-east of New Zealand.

The Sparta is holed beneath the waterline and stuck in heavy sea ice.

Some of the crew who had boarded lifeboats are now back on board.

The Rescue Coordination Centre New Zealand (RCCNZ) said in a statement that the crew had worked overnight to stabilise the Sparta.

Chris Wilson, from the RCCNZ, said crew had been pumping water from the hold and moving cargo around the boat.

"They've made good progress - the vessel is certainly in a safer position than it was yesterday," she said. "With Sparta now more stable, the vessel is the safest place for them."

The New Zealand air force Hercules, which carried out the drop, will spend the night at an airstrip near the McMurdo Station in the Antarctic.

It will refuel there before returning to Christchurch on Sunday.

A number of ships are on their way to assist the vessel but all are days away and being hampered by heavy sea ice.

Cargo overboard

The first distress call from the Sparta was picked up at about 0300 New Zealand time on Friday (Thursday 1400 GMT), when it was confirmed the ship east of the Ross Sea and taking on water.

It has a 30cm (1ft) hole in the hull beneath the water line and was listing at an angle of 13 degrees and taking on water, according to the RCCNZ.

The crew comprise 15 Russians (including the captain), 16 Indonesians and a Ukrainian.

There are no helicopters in the area and rescue authorities say the best option is for another vessel to come to the Sparta's aid.

But all three tasked with assisting are facing difficulties reaching the ship, said RCCNZ:

The Sparta's sister ship, Chiyo Maru No 3, is about 290 nautical miles away and does not have ice-cutting capability

The New Zealand vessel San Aspiring, which has some capacity to move through ice, is making its way towards the Sparta but is at least four days away

A third vessel is only 19 nautical miles away, but is hemmed in by heavy ice and unable to proceed towards the Sparta.

The ice surrounding the ship is estimated to be up to 1.5m thick, it said.

But weather conditions are currently good, calm and about 3C (37F).