Glenn Inwood, a Japanese Institute of Cetacean Research spokesman, said the crew had restored generator power and will test the engines later on Tuesday.
If the engines failed, the stricken vessel will be towed out of the area by other ships in the whaling fleet, said Inwood, but did not specify any port.
He said getting the ship out of the area as quickly as possible was "on everyone's minds" whether or not it was towed or moved out under its own power.
Japanese officials have denied the possibility of an oil spill, saying the fire which broke out below deck did not cause any structural damage to the ship.
But officials in New Zealand and environmentalists are concerned the ship could become trapped in moving ice and begin leaking some of the 1.3 million litres of oil load, though none has yet escaped.
"The consequences of anything happening there are so disastrous we want to remove the threat"
Steve Corbett, Maritime New Zealand
The 8,000-tonne Nisshin Maru is currently lashed to two other whaling ships about 100km from the world's largest Adelie penguin breeding rookery, at Cape Adare on the Antarctic coast.
Japanese officials have rejected all offers of outside help, drawing a warning on Monday from Helen Clark, New Zealand's prime minister, that Tokyo faced international condemnation if the incident sparked an environmental disaster.
She said Japan should reconsider its annual whale hunts in the Southern Ocean after this episode.
Steve Corbett, a Maritime New Zealand spokesman, said the threat of environmental disaster from the drifting ship was small but significant.
"There is a risk ... no matter how small it is, and it is small, we can't afford to take any chances with that environment," he said.
"The consequences of anything happening there are so disastrous we want to remove the threat."