* Australians arrive in Darwin after evacuation from Japan
* Holidaymakers to spend two more weeks in quarantine
* Australian PM to decide whether to extend travel curbs (Adds travel ban extension; paragraph 4)
By Colin Packham
SYDNEY, Feb 20 (Reuters) - More than 150 Australians arrived home on Thursday to begin two weeks of quarantine after finally leaving a cruise ship docked in Japan on which more than 600 people had contracted a new coronavirus.
Since Feb. 3, the Diamond Princess, owned by Carnival (NYSE:CCL) Corp CCL.N , has been quarantined at Yokohama, south of the capital, Tokyo, with 220 Australian holidaymakers among the 3,700 aboard initially.
Prime Minister Scott Morrison said 170 Australians were evacuated to the northern port city of Darwin, with 47 left in Japan after either getting infected or deciding to wait out the rest of their quarantine on the ship.
"The continuing coronavirus infections in mainland China make it necessary to continue the travel restrictions on foreign nationals entering Australia for a further week to 29 February," Morrison said in a statement.
The Australians coming home from Japan were all screened on arrival at a quarantine facility in Howard Springs, said Di Stephens, a health official in the Northern Territory.
"There were six people off that plane identified as having minor sniffles and sore throat that we have separated completely," Stephens told reporters in Darwin.
Swabs would be taken in the afternoon from the six, who went straight into isolation, she added.
Earlier, television images showed a Qantas Airways QAN.AX plane chartered to evacuate the Australians arriving in Darwin just before 10:00 a.m. (2300 GMT).
All 170 evacuees were required to be symptom-free when checked by Japanese health officials before they boarded, although Australia's chief medical officer, Brendan Murphy, has said some might still have the virus.
Since Feb. 1, Australia has barred entry to those arriving directly from mainland China, except for citizens and permanent residents, citing a need to stop the spread of the flu-like virus that emerged in China late last year.
On Monday, China's ambassador to Australia criticised the curbs as "harsh" and an "overreaction". has said Canberra would be guided by medical advice, despite growing pressure on the economy.
The epidemic could shave 0.2 percentage points off economic growth in the year's first quarter, Australia's top central banker said this month. China is Australia's largest trading partner and a major source of tourists and fee-paying students.