Legault's office had just $37,000 left at the end of the last fiscal year — or 0.2 per cent of her overall budget.
The information commissioner is an ombudsman for users of the Access to Information Act, handling complaints about delays, fees, and difficulties in obtaining records from federal agencies.
The access law allows people who pay $5 to request a variety of records from federal agencies, from correspondence and briefing notes to audits and hospitality receipts.
Departments are supposed to respond within 30 days or provide good reasons why more time is needed.
In her annual performance report, tabled recently in Parliament, Legault said she enjoyed successes in 2013-14, closing the most complaint files in three years, improving productivity and pursuing numerous legal cases.
However, the number of new complaints rose by 30 per cent. It followed a nine-per-cent increase in 2012-13.
"This growth in workload occurs in the context of significant financial restraint measures that have had a large impact on my budget," Legault says in the report.
"With the incoming complaints volume showing no sign of abating, and with no financial flexibility, it is increasingly difficult, if not impossible, to keep ahead of demand and respond to complainants in as timely a manner as possible."
It means a gap of about six months between the time a complaint about lack of access to records is received and the time it is assigned to an investigator.
The commissioner's budget must absorb salary increases next year, leaving her concerned "we have been stretched to the limit."
"It is my responsibility to alert the government and Parliament to the risks that the organization is facing," Legault adds in the report.
"Without additional funding, I will no longer be able to carry out my mandate responsibly and ensure full respect of Canadians' rights of access to information. As such, I intend to seek the support of the Treasury Board to obtain the necessary financing."
Natalie Hall, a spokeswoman for Legault, said discussions with various officials "are ongoing."
Stephanie Rea, a spokeswoman for Treasury Board President Tony Clement, had no comment on the status of Legault's request.
The commissioner and the minister don't always see eye-to-eye on Access to Information issues.
Legault plans to release a report in coming weeks recommending measures to modernize the access law, which has changed little since taking effect on Canada Day 1983.
Clement has rejected calls from Legault, pro-democracy groups and opposition MPs to update the act, saying it is a good piece of legislation.
In the Conservatives' latest open government plan, Clement promises more automatic release of data on contracting, spending and scientific research.
Proactive disclosure should "provide a release valve" for the access system, resulting in fewer formal requests, he says.
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