Newly released polling results suggest the BC Liberals are leading the NDP by more than 12 per cent ahead of high-stakes byelection in Nanaimo this week that threatens to disturb the balance of power in the legislature.

According to a survey conducted by Mainstreet Research last week, 44.7 per cent of decided voters said they supported the Liberals, while 32.2 per cent said they were backing the NDP.

"No matter what angle we look at it, the BC Liberals are ahead of the BC NDP in Nanaimo with the vote to be held on Wednesday,” Mainstreet president and CEO Quito Maggi said in a statement.

The Liberals were most popular among men (48.2 per cent of leaning voters) and those over the age of 65 (49 per cent).

By comparison, 35.7 per cent of those who said they were leaning towards the NDP were women, and respondents were almost evenly split between the 35-49, 50-64 and 65-plus age categories.

The Greens had the support of 13.7 per cent of respondents, and the BC Conservatives polled at 7 per cent.

Maggi said all of the metrics considered in the poll put the Liberals in the lead, even if only slightly so.

"Probably, I would say this election will be closer than what our poll suggests, but still gives an edge to the Liberals," he said.

“No matter if we ask for party names or candidate names, the BC Liberals are leading.”

The NDP and Liberals agreed that the race will likely be a nail biter, but the premier emphasized that pollsters like Mainstreet have been wrong before.

"They ask for snapshots in time," John Horgan said. "Whether that's accurate—that's something we'll find out on Wednesday."

Voters in the Vancouver Island city will elect their new MLA Wednesday. The NDP's Leonard Krog left his seat back in October to become the mayor of Nanaimo, triggering a byelection that will test the party's slim minority in Victoria.

A Liberal victory in the byelection would give the party 43 seats, tying it with the 43 seats held by the NDP and Greens.

Just under 20 per cent of registers voters have cast their ballots in advance polls.

According to Mainstreet, 735 eligible voters in Nanaimo were surveyed on Jan. 23 and 24. The poll results carry a margin of error of 3.54 per cent 19 times out of 20.

With files from CTV Vancouver's Bhinder Sajan

The full poll results follow. Viewing this on our mobile beta site? Tap here for a compatible version.