Canadian-owned Yeelirrie uranium mine, about 500km north of Kalgoorlie, was given the tick of approval by Environment Minister Melissa Price on April 10, according to an Environment Department document.

Prime Minister Scott Morrison triggered the May 18 election on April 11.

"This is yet again looking like another shonky deal by this government," Mr Shorten told reporters in Melbourne on Friday.

"Pretty big decision. A lot of money at stake. Made in the dead of night, the day before the election's called.

"There are questions for this government to answer."

The Conservation Council of WA and traditional owners are in the midst of a legal fight over the mine after taking their battle to the Court of Appeal last month.

State approval was given just weeks before the WA election in 2017.

The federal government had previously indicated it wouldn't make a decision until the WA appeal was complete.

Labor's environment spokesman Tony Burke says no detail is known about the approval, accuses Ms Price of being in hiding.

"I want to find out what on earth has happened," he told ABC radio.

"You need to know whether the conditions that have been put in place are fair, you need to know whether the environmental assessment has been dealt with rigorously."

Senior government minister Mathias Cormann has claimed the approval was given on March 5 but additional administration meant it wasn't finalised until this month.

"This is business as usual," he told Sky News, adding the mine faced 32 strict environmental conditions.

But Greens senator Jordon Steele-John is calling on Labor to tear up the "absolutely disgraceful" approval if it wins government.

"We cannot have a situation where this mine goes ahead," he told Sky News.

The Minerals Council of Australia has welcomed the approval, saying the project will create jobs in WA and claiming it will help the transition to a lower carbon economy.

Australian Associated Press