(Adds comment from oil-producing province, industry group)
CALGARY, Alberta, Aug 10 (Reuters) - British Columbia will not allow Kinder Morgan Canada Ltd to begin work on public land for its Trans Mountain pipeline expansion until it "meaningfully" consults aboriginal communities, provincial officials said on Thursday.
The $5.5 billion project through British Columbia, which secured federal government approval last year, would almost triple the capacity of the current Trans Mountain pipeline.
The project's prospect has become more uncertain since a left-leaning government took power in British Columbia in June, although the administration has softened its rhetoric since taking power last month.
British Columbia Environment Minister George Heyman told reporters in Vancouver it is unlikely that Kinder Morgan will be able to begin work on public land by its September construction target.
British Columbia will also seek to participate in court cases against federal approval of the project, Heyman said.
Kinder Morgan said in a statement it takes the British Columbia government's comments seriously and remains willing to meet with provincial officials. The company, which has scheduled most major work for next year, said Heyman's announcement will not affect its timeline for Trans Mountain construction.
But shares in Kinder Morgan Canada and Houston-based parent Kinder Morgan Inc fell soon after the minister's comments and ended down 3.7 percent and 1.8 percent respectively. The benchmark Toronto share index shed 0.9 percent.
Kinder Morgan's project is critical for Canadian crude producers as they say they need it to access new markets and command better prices. Currently, their landlocked products trade at a discount to the West Texas Intermediate benchmark.
Heyman said the provincial government has not accepted five of Kinder Morgan's eight plans to mitigate the project's environmental impact because they do not adequately address aboriginal consultation.
"Until those plans are completed, Kinder Morgan, with the exception of private land ... cannot put shovels in the ground," the minister said. He did not specify the benchmark for consultation, a requirement under Canadian law, to be done "meaningfully."
University of British Columbia law professor Jocelyn Stacey said, given the government's stance on indigenous issues, it will likely hold Kinder Morgan to a high standard.
Alberta Premier Rachel Notley said British Columbia is upholding high standards and she does not think the province will block the project. The pipeline begins in Alberta, home to almost all of Canada's oil production.
The Canadian Association of Petroleum Producers industry lobby group said British Columbia was "not unreasonable" in protecting its interests. (Reporting by Ethan Lou; Editing by Phil Berlowitz and Lisa Shumaker)