The NT Government has broken the law by using taxpayers' money for advertisements that were inaccurate and promoted the political interests of the ruling Country Liberals party (CLP), the Auditor-General has found.

The ads, published late last year, stated that Opposition and crossbench MLAs had blocked proposed laws that would allow police to search cars for the drug ice.

But Northern Territory Auditor-General Julie Crisp found that to be untrue.

"The [proposed change] had not progressed to the point where it was being debated therefore it is my opinion that the advertisement includes statements that are misleading and factually inaccurate," Ms Crisp's latest report reads.

"The ice drug laws were not blocked as communicated in the advertised content."

Labor and the crossbenchers had voted against an urgency motion to rush the laws through the Parliament's September sitting.

The laws were instead debated and passed in November.

Ms Crisp also found that the ads promoted the political party interests of the CLP and declared that they breached the Public Information Act.

Independent MLA Gerry Wood described the ads as gutter politics last year and welcomed the Auditor-General's finding.

"This has come out of the office of the Chief Minister and it's been shown by the Auditor-General it was a load of rubbish," Mr Wood said.

"It was just a bunch of lies that they put out simply to gain some political advantage."

Mr Wood said he wanted an apology from the Chief Minister, but Adam Giles said the ads highlighted an important issue.

"We'll put the apology out and say we shouldn't have put their party political preference of who they were, whether they were independent or Labor, but we won't apologise for the ad itself," he said.

Finding against 'On Track' ads

The Auditor-General also found against the Government's 'On Track' advertising campaign, which the ABC confirmed had cost $428,000.

Ms Crisp acknowledged that the ads were independently developed to boost business confidence, but said the 'on track' phrase could be linked to the Country Liberals' 2012 election campaign.

The 'On Track' NT Government advertisements . ( ABC: Xavier La Canna )

She said that the ads broke the law by including a message that may promote a particular political party.

"I am of the opinion that the referred matter constitutes a contravention ... of the Public Information Act, in that the content of the information may be regarded as promoting political party interests [whether express or implied]," she said in her report.

In response to the criticism, the Department of Chief Minister was quoted in the report saying they "respectfully disagreed" with the findings.

"At no time in any of the four focus groups was it raised by any of the participants that the phrase reminded them of a particular political party or political slogan," the department said.