A B.C. Supreme Court judge has ruled that part of the province's tough drinking and driving law is unconstitutional, while upholding the bulk of the legislation.

Lawyers had argued that B.C.'s automatic roadside driving prohibition law, which went into effect in September 2010, is unconstitutional because the province didn't actually have the jurisdiction to impose the rules as federal law governs criminal offences that involve blood alcohol content over 0.08 per cent.

Lawyers also argued that the law violates the Charter of Rights and Freedoms, because it results in unreasonable search and seizure and gives too much power to the roadside police and allows for no appeal mechanism.

The court ruled Wednesday that B.C. was within its jurisdiction in putting in place the laws that target drivers with a blood alcohol content over 0.05 per cent, because the province should be allowed to regulate licensing of drivers and put in measures to enhance highway safety.

However, the judge also found that B.C.'s laws do violate the Charter when a driver is screened and found to fail a breathalyzer test by blowing above 0.08 per cent, as it gives the police power to impose criminal-like consequences with no opportunity given to the motorist to challenge the decision.

Police take a breathalyzer sample from a driver. (CBC)

The Honourable Mr. Justice J.S. Sigurdson wrote in his decision that under criminal law, a driver has a number of protections that are essentially stripped under B.C.'s new law for drivers who fail the breathalyzer test at a level of 0.08 or above.

"The search under the ARP regime in this case results in consequences similar to those arising out of a criminal investigation, but provides a far less meaningful basis upon which to challenge the legitimacy of those consequences," Sigurdson wrote.

"I conclude that this is a significant issue in terms of the reasonableness of the law."

Sigurdson ruled that in the case of those who blow in the 0.05-0.08 warning range, B.C.'s law isn't as big a problem because the consequences are much lighter.

The judge asked the lawyers for both sides to return to make arguments on how to resolve the infringement.

The court's final decision would have immediate implications for other provinces in the process of enacting similar legislation.

Last week, the Alberta legislature tabled a bill that would allow police to immediately suspend the licence of anyone caught driving with blood alcohol content over 0.05. The penalties include the power to keep licence suspensions in place for people caught with more than 0.08 of blood alcohol content until their cases are dealt with in court.

With files from the CBC's Stephen Smart and Jeff Davies