An exhausting seven-year wait for US President Barack Obama to approve, or not, a controversial North American pipeline has not soured Canadians' view of their southern neighbors, a study said Tuesday.

Polling by Pew Research Center found that Canadians remain "generally satisfied with their country's current relationship with the United States."

The nonpartisan Washington-based think tank cited a telephone survey of 1,004 Canadians in May of this year that showed 81 percent of them would maintain or reinforce Canada's relationship with the United States.

Only 16 percent of respondents said the two nations "should be less close," it added.

Furthermore 68 percent said they have a favorable view of the United States -- a sentiment that has held fairly steady over the years, apart from a dip after the start of the Iraq War in 2003 and a low point (55 percent) in 2007.

This is despite the Obama administration's delay in ruling on the Keystone XL pipeline, which Ottawa supports.

The pipeline holdup has been a top irritant in the bilateral relationship.

The 1,179-mile (1,900-kilometer) TransCanada-built pipeline would transport crude from oil sands in energy-rich Alberta province to a network of pipelines that reach across the United States to refineries on the shores of the Gulf of Mexico.

Because the project crosses a border, the US State Department must give its approval first, but the case is still being studied seven years after TransCanada made its first request.

Obama has the final say, which is now expected before he leaves office in 2017.

The last polling on the topic in May found that 42 percent of Canadians supported the construction of the pipeline.

In the United States, environmentalists have strongly opposed it because the crude comes from what they describe as "tar sands," which require a more carbon-intense process of extraction and processing.

Pipeline opposition is also widely viewed as a proxy fight against global warming.