The Australian Greens will push parliament for a debt guarantee for Qantas with "strings attached" but will fight any move to amend the Qantas Sale Act.
Prime Minister Tony Abbott supports changing the law to allow Qantas to be majority overseas-owned but says he won't be offering the airline a "free ride on the taxpayer".
"Let's not have Qantas competing with Virgin and others with one hand tied behind its back," Mr Abbott told Fairfax radio on Friday.
"But I do have to say there is no free ride on the taxpayer for private companies."
Greens deputy leader Adam Bandt said the minor party might put through legislation to protect local jobs if the federal government "comes to its senses" with assistance measures for the national carrier.
"That may well require legislation that comes through parliament," he told reporters in Canberra.
However, the party will oppose moves to unshackle Qantas from foreign ownership restrictions through a repeal of the Qantas Sale Act.
Mr Bandt said Australia needed a national flag carrier and foreign ownership would mean jobs being sent offshore.
Qantas says it is hamstrung by the law - introduced when Labor sold the airline in the 1990s - which caps foreign ownership of the company at 49 per cent, thereby limiting its access to capital.
However, Qantas boss Alan Joyce admits there is little political and community appetite for changing the law, and has instead asked the government to consider support such as a debt guarantee.
Labor remains opposed to allowing majority overseas ownership of Qantas but is open to the government providing an assistance package.
Virgin Australia says it's happy to see Qantas relieved of its ownership restrictions but disputes the need for government support.