Amazon has been accused of threatening to fire workers who speak out about climate change.

The company warned two employees they could be sacked if they continued to speak publicly about Amazon's environmental policies.

In a statement on Twitter, Amazon Employees for Climate Justice, said several technology workers were told they were in breach of the company's external communications policy.

The group said the threats came a month after Amazon announced its climate pledge policy and committed to carbon emissions goals for the first time.

AECJ said it had been calling on Amazon to take action on climate change for nearly a year and it also organised a walk out by workers to support the Global Climate Strike in September.

Amazon tech worker Maren Costa, a user experience principal designer, was threatened with termination for speaking to the Washington Post.

"Now is a time when we need to have communications policies that let us speak honestly about our company's role in the climate crisis," Ms Costa said.

Market snapshot at 9am (AEDT): The Dow Jones index rose 1.2 per cent or 330 points to 28,869.

The Dow Jones index rose 1.2 per cent or 330 points to 28,869. The S&P500 increased 0.8 per cent to 3258. It's the benchmark's 11th record high in eleven sessions.

The S&P500 increased 0.8 per cent to 3258. It's the benchmark's 11th record high in eleven sessions. The Nasdaq rose 1.3 per cent to 9,092.

The Nasdaq rose 1.3 per cent to 9,092. Data from the US Labor Department showed a fall in the number of claims for unemployment benefit last week.

Data from the US Labor Department showed a fall in the number of claims for unemployment benefit last week. The optimism about the China stimulus boosted the FTSE 100 index in London to 7,604, up 0.8 per cent.

The optimism about the China stimulus boosted the FTSE 100 index in London to 7,604, up 0.8 per cent. Spot gold rose to $US1526 an ounce with some investors not convinced that the rally on a Wall Street is sustainable.

Spot gold rose to $US1526 an ounce with some investors not convinced that the rally on a Wall Street is sustainable. Oil prices picked up with Brent crude at $US66.07 a barrel.

Oil prices picked up with Brent crude at $US66.07 a barrel. The Australian share market look set for a good start with the ASX/SPI 200 index up 0.8 per cent to 6,679.

The Australian share market look set for a good start with the ASX/SPI 200 index up 0.8 per cent to 6,679. The Australian dollar fell back from a five-month high to $US0.699 on a higher greenback.

"This is not the time to shoot the messengers."

"This is not the time to silence those who are speaking out."

In response, Amazon said employees are encouraged to work within their teams and can suggest improvements on how the company operates through internal channels.

"Our policy regarding external communications is not new and, we believe, is similar to other large companies," an Amazon spokeswoman said.

"As with any company policy, employees may receive a notification from our HR team if we learn of an instance where a policy is not being followed."

In September, Amazon's boss Jeff Bezos announced the company plans to rely entirely on renewable energy by 2030 and have net zero carbon emissions by 2040.

The latest revelations had little impact on Amazon shares, which jumped 2.7 per cent overnight amid a broad based rally.

China economic stimulus sees stocks rise

New economic stimulus from China saw US stocks hit new record highs on the first trading day of the year.

China's central bank said it would lower the amount of cash that banks need to hold on their books.

It's the eighth cut since early 2018 by the People's Bank of China.

The PBOC will cut banks' reserve requirement ratio by 50 basis points on Monday.

The move releases more than $US100 billion to bolster China's economy, which is growing at the slowest pace in nearly 30 years.

Investors are also optimistic that an initial trade deal between the US and China will be signed on January 15th.

US president Donald Trump confirmed the date on Tuesday.

Arrest warrant issued for former Nissan CEO Carlos Ghosn

Lebanese authorities have received an Interpol arrest warrant for the former Nissan chairman Carlos Ghosn.

Mr Ghosn fled to Lebanon on Tuesday on a private jet to escape what he called "rigged" justice system in Japan.

He is facing charges related to alleged financial crimes while at the helm of Nissan.

Mr Ghosn is accused of hiding income and accepting payments from car dealerships in the Middle East.

Nissan sacked him as chairman accusing him of misconduct including hiding his salary while he was chief executive.

He denies the charges.

Interpol's Red Notice requests that Lebanon arrest Mr Ghosn pending extradition proceedings.

However, a senior Lebanese security official told Reuters it was not clear if Ghosn would be summoned for questioning.

Turkey has detained seven people on the suspicion of helping Mr Ghosn to leave Japan via Istanbul to Lebanon.

Mr Ghosn lived in Lebanon when he was a child and has Lebanese, French and Brazilian citizenship.