(Adds byline and changes dateline to Victoria, adds statement from New Democrats leader)
VICTORIA, British Columbia, June 29 (Reuters) - British Columbia's Liberal government was defeated on Thursday in a non-confidence vote, as expected, paving the way for the left-leaning New Democrats to rule the Western Canadian province for the first time in 16 years.
The prospect of such a government has unnerved investors in Canada's third-most populous province, not least owners of oil and gas projects such as Kinder Morgan Inc's C$7.4 billion Trans Mountain pipeline expansion project, which the New Democrats have vowed to halt.
On Thursday, seven weeks after a knife-edge election, New Democratic Party (NDP) lawmakers, backed by the Green Party, used their majority of 44 in the 87-member legislature to introduce a non-confidence amendment in the Liberal government's Throne Speech.
British Columbia premier Christy Clark is expected to inform the province's nominal head, Lieutenant-Governor Judith Guichon, that she will resign. Guichon is then expected to invite NDP leader John Horgan to form a government.
"British Columbians are closer than ever to getting the new leadership they voted for," Horgan said in a statement. "And we're ready to form a strong, stable government."
The Greens struck an agreement in late May to back the NDP and oust the Liberals after a May 9 general election reduced Clark's party to a minority. But with only one seat more than the Liberals, a Greens-backed NDP government is fragile and few expect it to survive the four-year term.
The right-leaning British Columbia Liberals are unaffiliated with the left-leaning Liberals in power federally.
The NDP and Greens, which will form the first minority government in the province in 65 years, have accused the Liberals of trying to cling to power by stealing their election promises and introducing them as last-minute legislation to delay being voted out.
Green leader Andrew Weaver said in a statement after Thursday's vote he was encouraged that the Liberals had adopted the policies of the NDP and his party.
"This is an historic opportunity for all 87 MLAs (members of legislative assembly) to work together," he said. (Reporting by Nicole Mordant in Vancouver; additional reporting by Ethan Lou in Calgary, Alberta; Editing by Sandra Maler)