VICTORIA - Two British Columbia byelections to fill vacant Metro Vancouver seats are being fought against a much larger political backdrop than who wins or loses.

Premier Christy Clark's Liberals, the New Democrats and the Greens are knocking on doors and waving signs to court votes and field testing tactics and attitudes in advance of the provincial election 16 months away.

The byelections Tuesday in Vancouver-Mount Pleasant and Coquitlam-Burke Mountain won't change the balance of power in the legislature, currently at 48 Liberals, 33 New Democrats, two independents and two vacancies, but they start a countdown to the May 2017 election.

A political analyst said Clark's Liberals have jumped on the idea of the sharing economy in an effort to deflect unfulfilled election promises of a liquefied natural gas bonanza.

University of Victoria public policy expert Michael Prince said John Horgan's New Democrats are determined not to repeat the disastrous results of two recent NDP campaigns - Thomas Mulcair's federal election slide and Adrian Dix's demoralizing defeat in the B.C. election.

The Green Party, with one elected member, is presenting itself as the alternative to B.C.'s traditionally polarized left-right political divide, he said.

“The 2017 election is on,” said Prince.

“The Liberals are trying to figure out a way of having an economic development story line that isn't simply just gas, gas, gas,” he said.

“The NDP, perhaps, will take a page from Justin Trudeau's game book and come out with a more robust platform with all sorts of promises, not one big one, like, 'we're going to bring in a poverty reduction plan.”'

Mount Pleasant is a New Democrat stronghold and youth advocate Melanie Mark is expected to hold the seat for the party after long-time member Jenny Kwan's move to federal politics.

Mark's up against Liberal challenger Gavin Dew and Green candidate Pete Fry.

Burke Mountain in suburban Coquitlam has been in Liberal hands since 2009.

Community leader and businesswoman Joan Isaacs is running for the Liberals and Autism Support Network executive director Jodie Wickens is the NDP candidate. Green Party candidate Joe Keithley, well-known as the driving force behind the punk band D.O.A., has also jumped into the byelection.

NDP Leader John Horgan said affordability is the big issue he's hearing on door steps. Food and housing costs are going up, but their pay cheques haven't increased.

“On top of that, is the sense the premier and her government is just not there for regular people. The slogan of families first is long forgotten and it seems corporations first is what people are echoing back to me.”

He said residents can expect more NDP challenges of the premier and the Liberal record, including anti-government advertising blitzes, which started in recent weeks.

“The last time we let the government off the hook,” Horgan said of the 2013 provincial election. “I don't have any intention of doing that.”

The B.C. Liberal Party noted that since 1963 governing parties have only won four of 32 byelections, but its candidates look to the future while the NDP sticks to old ideas and name calling.

“Today's B.C. Liberals are bringing forward new ideas to strengthen what is already the strongest provincial economy in Canada, and the NDP is taking voters for granted with a negative campaign that offers no new ideas on how to build a better province,” said a statement from the party.

Prince said Liberal moves to examine the so-called sharing economy through informal polling are signals the government wants to move in a new direction and attract new voters ahead of the next election.

Issacs pledged during her campaign that she would work to build sharing technologies such as ride-share programs Lyft and Uber and lodging website Airbnb.

“The Liberals are looking for an economic development story that isn't just pinned on resource extraction,” Prince said.

He said recruiting former finance minister Carole Taylor as a policy advisor and warming to sharing are shrewd political manoeuvres by a party looking to shore up its traditional base and find new, young voters ahead of an election.

“This social-sharing economy stuff is trying to figure out their new age politics,” Prince said. “It's what is the new age and the new wave and how a dynasty government four terms in power wants to get a fifth term.”