The government contracted the Wagner Corporation to build the $48.8 million complex near Toowoomba, which opened earlier this year.
Wellcamp is now owned by the company, but has been leased back to the state for 12 months for an undisclosed sum.
Another 800-bed facility, worth $350-400 million, is being jointly built by the state and federal governments at Pinkenba, near Brisbane Airport.
Ms Palaszczuk defended Wellcamp, saying the project was needed because the former federal government failed to take responsibility for quarantine.
"Scott Morrison failed to act, and we now have a dedicated quarantine facility for whatever may happen in the future," she told reporters on Wednesday.
"There's also one in Victoria, there's also one in Western Australia, there's one in the Northern Territory, and Queensland should have one as well."
The premier has refused to reveal how much taxpayers have paid to lease Wellcamp, and the tender process for the project remains opaque.
She has said information surrounding the deal is commercial-in-confidence, however the auditor-general is seeking more information.
Liberal National Party leader David Crisafulli insisted there were no confidentiality provisions because there was no competitive tender process for Wellcamp.
He claimed the combined construction and lease cost was more than $200 million, and that Queenslanders still did not own any part of the asset.
"I have grave concerns that it is going to be a bill that Queenslanders continue to pay for a long, long time," Mr Crisafulli told reporters.
"The lease expires at the start of next year, and the government has already flushed millions of dollars down the drain on a facility that Queenslanders will never own."
The premier said the government has not decided whether to renew the Wellcamp lease, but the complex could possibly house flood or domestic violence victims.
Mr Crisafulli called on her to reveal the full lease cost of Wellcamp and outline what her plans are for the complex.
"If the lease was to be renewed at a time when there's half a dozen people in it, I would suggest that tells you everything you need to know about the priorities of this government," the LNP leader said.