The federal government's information watchdog, which is preparing to be abolished in weeks, seems likely to be spared by the Senate at the 11th hour.

But even if crossbenchers vote to save the Office of the Australian Information Commissioner, it might lack the staff to continue its work overseeing privacy and freedom of information law, and encouraging public servants to be less secretive.

Attorney-General George Brandis announced in May the agency would close by the end of this year.

Its Canberra office, which had up to 25 staff, has just three left, though another 68 employees in Sydney work mostly on privacy issues.

The decision to gut the office caught many by surprise because the National Commission of Audit, which had recommended abolishing dozens of other bodies, suggested the office should remain. The audit commission also urged the government to prioritise transparency.

The information office's fate now rests with crossbench senators, in particular the fragmented Palmer United Party. Liberal Democrat David Leyonhjelm, a classical liberal who supports restraints on government authority, is understood to back the watchdog, as is Democratic Labour senator John Madigan.

The Coalition, Labor and the Greens are all lobbying crossbenchers ahead of the release of a Senate committee report on the information office next week. However, the position of the Palmer senators, who are distracted by party disunity, remains unclear.

The government is rushing to pass legislation that would fold the office's FOI work into a proposed new super tribunal, which it says will remove unnecessary layers of bureaucracy.

The government also plans to move the office's privacy functions into the Human Rights Commission, though commission president Professor Gillian Triggs told the Senate that proposal was unworkable.

"If this bill is passed, we will continue to do what we are doing ... but we will have this bubble in the middle of it, where you have a privacy commissioner with staff I will allocate to him notionally, but the curious phenomenon under this bill is that those staff would not, under any circumstances, be accountable to the commission," she said last week.

"That is simply unworkable, because of the way in which the financial requirements are and in relation to all sorts of staffing matters and other legislation."

If the Senate blocks the bill, it would send FOI law into an administrative limbo, in which the Information Commissioner Professor John McMillan and his FOI commissioner James Popple have legal duties they must perform but no staff to help them.

Most public submissions to the Senate have argued against abolishing Professor McMillan's office, citing the need for independent scrutiny of FOI decisions without imposing the costs of going to court.

Labor's legal affairs spokesman Mark Dreyfus said the proposal would weaken FOI and came from a government desperate to hide what it was doing from the Australian people.

Greens senator Lee Rhiannon said the legislation was a serious backwards step. "This will strengthen people's concern that this is a government of secrecy."