The U.S. government is escalating a dispute over a seldom-used B.C. liquor law that it argues discriminates against wine producers south of the border.

On Friday, the Trump administration announced it has asked the World Trade Organization to establish a panel to scrutinize B.C.'s law banning non-local wine from grocery store shelves.

The regulation, which was introduced back in 2015, was previously challenged in a complaint by Barack Obama's government.

"Discriminatory regulations implemented by British Columbia are unfairly keeping U.S. wine off of grocery store shelves, and that is unacceptable," U.S. Trade Ambassador Robert Lighthizer said in a statement.

"(The Trump administration) will continue to hold our trading partners accountable by vigorously enforcing U.S. rights under our trade agreements and by promoting fair and reciprocal trade."

Under B.C. law, there are two ways for grocery stores to sell alcohol. The first is called the store-within-a-store model, which lets them sell beer, wine and hard liquor, including imports, in separated section of the store with its own cashiers. The second option, called wine-on-shelf, lets them stock wine alone alongside groceries.

If they choose the latter, they are required to sell only B.C.-produced wine.

But only 27 grocery stores across the entire province use the wine-only model, according to a spokesperson with B.C.'s Ministry of Attorney General, which oversees liquor regulations.

That amounts to less than two per cent of the grocery stores in B.C., according to Statistics Canada data from 2016.

Speaking at a news conference Friday, B.C. Premier John Horgan brushed off the U.S. criticism.

"The entire Trump administration seems to be lashing out in every direction on every issue," Horgan said. "Now it's wine. It was steel, it was aluminum, it's autos. There doesn't seem to be a sector (where) Mr. Trump doesn't feel that he's aggrieved."

And with tough NAFTA negotiations continuing between Canada and the U.S., Horgan said he would not be wading further into the debate.

According to the Trump administration, U.S. wine exports into B.C. topped $72 million last year, and made up 10 per cent of the province’s wine market.