Full chocolate production could be restored at Hobart's Cadbury factory by Friday afternoon, following a cyber attack which halted production on Tuesday night.
John Short, the state secretary of the Australian Manufacturing Workers Union, said he had been advised limited production had restarted at the Claremont factory.
"Hopefully by tomorrow (Friday) afternoon shift they may well be in full production," he said.
"The IT people have been on to it and they've been able to clear the problem so it sounds like it's going to be great news."
Cadbury was hit by the global cyber attack that started in the Ukraine earlier in the week and spread to businesses around the world, including Australian branches of companies TNT Express and DLA Piper Lawyers.
All of the IT networks of Cadbury's parent company Mondelez International were affected globally.
A spokeswoman said the multinational was still working to fully resolve all the problems caused by the attack.
Mr Short said workers at the Claremont site got some peripheral facilities, including boiler rooms, operating on Thursday morning.
"They were testing to make sure the systems are sound and from the advice I've received hopefully by tomorrow afternoon it should be OK," he said.
Mr Short said it was a good result to have the production back so quickly.
"To get it back and running after such a big attack, I think they should be commended for it," he said.
"I know some of the other companies around the world are probably not finding it as easy to overcome the problems."
Joel Scanlan, a cyber security lecturer at the University of Tasmania, said businesses generally could protect themselves fairly well from cyber attack.
"At the end of the day, you cant get risk to zero," he said.
He said the most important step was ensuring IT systems were properly patched.
"With these big attacks we're seeing large multinationals that have lots of these sorts of systems in place but they're not being targeted, what's actually being targeted is those older unpatched systems," he said.
The virus, which started with a small piece of computer code inside a word or PDF document, shut computers down and demanded a ransom of 300 bitcoins, or $395 to unlock user's data.
