OTTAWA (AP) — Newly obtained documents from the Canada Border Services Agency confirm what union officials have been saying for years: The agency's Web site that shows waiting times at the U.S. border is sometimes inaccurate.

For five years the agency has posted waiting times for the 22 busiest crossings, including four between British Columbia and northwest Washington state.

The agency's goal is to hold the wait within 10 minutes Monday through Thursday and 20 minutes Friday through Sunday and on holidays. Officials claim that Canada meets the goal at least 90 per cent of the time, but that has long been disputed by the Customs Excise Union Douanes Accise.

Four years ago an independent check by front-line border officers found widespread underreporting, in some cases by as much as two hours.

The "CBSA has not been reporting accurate wait times, and the times CBSA have been reporting are always shorter than the actual wait times," union President Ron Moran said.

On Sunday, the Canadian Press reported that an agency briefing note dated April 2008 acknowledged there has been no standard way to calculate how long travelers must wait to enter the country.

"Methods of estimating wait times are specific to each port and are conducted exclusively as a visual inspection by port personnel," said the document, which was obtained under Canada's Access to Information Act.

The Web listings "cannot be used as a predictor of exactly what the real-time wait will be when arriving at a port of entry," the note stated.

Agency charts obtained by CP, based on uneven data from 2003-2008, indicate that backups are generally much longer in the summer and on holidays but that there is much less fluctuation through the year for commercial truckers.

The documents did not shed light on the accuracy of a a similar Web site of U.S. Customs and Border Protection for entry to the United States or of some private business and state agency Web sites that also list waiting times at the border.

Responding to e-mail questions, Traci LeBlanc, a spokeswoman for the Canadian border agency, said the posted wait times have never been audited.

"The CBSA is currently developing an action plan to better measure border wait times, which includes reviewing potential technological solutions to improve the quality of the border wait time data being captured," LeBlanc said.

Agency officials met with their U.S. counterparts earlier this year in Tucson, Ariz., to discuss ways to record wait times more accurately in response to complaints from importers and exporters who say the lines have been getting longer.