OTTAWA 鈥� Canada's tax collectors often aren鈥檛 picking up the phone, and when they do, Canadians are being given incorrect information, a new federal audit reveals.

The into whether the Canada Revenue Agency鈥檚 nine call centres were providing Canadian taxpayers with timely access to accurate information, found that call centre agents only answered the phone about one-third of the time.

When the callers do get through to the call centre, the audit found that agents are giving Canadians incorrect information nearly 30 per cent of the time.

The auditor's office found this by calling into the call centres between March 2016 and March 2017 and asked the call agents general tax questions.

In a press conference, Ferguson said he finds the number of Canadians getting bad information from the tax agency "very concerning" because people rely on the CRA to give them the right answer.

"If people aren鈥檛 told the right date for when interest will be charged on what they owe, they may make a payment later than they should, and they may get charged interest that they weren鈥檛 expecting to get charged," said Ferguson, giving an example of the impact of the CRA staff鈥檚 erroneous information.

"Every time the answer that they get from the call centre isn鈥檛 a right answer, there鈥檚 always the potential that that is going to impact individuals," he said.

The auditor general estimates that based on this bad advice there is a real potential for Canadians to have made errors while filing their taxes.

Prior to the auditor general's examination, the CRA said it was meeting its targets for access and timeliness. The auditor general found that this was because the CRA had been overstating its success by not accounting for millions of blocked calls.

The auditor general discovered that the CRA blocked about 29 million calls, more than half of its 53.5 million total call volume, because the call centres could not handle the volume of calls.

These blocked callers were given a busy signal or message to go to the website or call back later. The blocking was done by a traffic team, and when the time the caller was waiting to get through approached two minutes, they were blocked.

鈥淓ach caller made an average of three or four call attempts per week. Even after several attempts, some callers did not always reach an agent or the automated self-service system,鈥� Ferguson said in the Fall 2017 report tabled in Parliament on Tuesday.

When callers were able to get through, 17 million were able to reach an agent, while 7.6 million went to automated self-serve options.

The CRA reported that about 90 per cent of callers are able to be connected to the automated self-service system or a call centre agent. However when the blocked calls are factored in, the Agency鈥檚 overall success rate dropped to 36 per cent.

The auditor general concluded that the CRA needs to step up its call centre service.

Ferguson said this is important because calling in for help is the main way for Canadians to get help with specific questions, or is the only way for those without internet access or who are not comfortable or able to use a computer.

"The Agency made a commitment under the Taxpayer Bill of Rights to give taxpayers accurate information," Ferguson said. "If taxpayers cannot get timely access to accurate information, they may file incorrect returns, miss filing deadlines, pay too little or too much tax (and later be subject to reassessment), or miss out on benefits they are eligible to receive."

In response to the auditor general鈥檚 report, National Revenue Minister Diane Lebouthillier acknowledged there is more work to be done.

She said the CRA will be updating its call centre technology to update callers on current wait times, improve agent training and implement a "national quality control team," as well as improve the quality and clarity of the information it gives Canadians.

"Our clients have a right to receive information that is clear and precise, when they need it," the minister said in a statement.

Responding to the findings, the opposition didn鈥檛 mince words.

"It鈥檚 bad enough when they get bad advice from people in the private sector, tax planners or accountants, that鈥檚 one thing. But this is the government itself. These are government officials themselves telling a taxpayer, telling a hardworking Canadian how to properly proceed, and when that鈥檚 wrong and they suffer because of it鈥� that is just unacceptable," said Conservative Leader Andrew Scheer.

NDP MP David Christopherson called it "deeply, deeply troubling" that above the expectations Canadians should have to be given correct information by the CRA, the tax agency tried to overstate its success rate for answering calls.

"The rights Canadians should have are not being respected, they鈥檙e not being honoured. In fact, this agency is trying to hoodwink Canadians."