A new poll released by a firm run by three Liberals suggests support for Rana Bokhari's party is on the decline in Winnipeg as election day nears.

Insight Manitoba polled a random sample of 3,454 Winnipeggers between March 26 and April 3 and found approval ratings for the Manitoba Liberal Party have slid by three percentage points in Winnipeg since the beginning of March. The party went from a 19 to 16 per cent approval rating in Winnipeg.

The drop coincides with a boost in support for the Manitoba Progressive Conservatives and the New Democrats in the Winnipeg battleground. Support for the NDP inched up from 21 to 24 per cent; approval for a Brian Pallister-led government rose from 35 to 38 per cent. The Greens remained steady at five per cent, according to the poll.

The number of undecided voters also shifted, from 20 per cent to 17 per cent in Winnipeg.

Reaction to Liberal decline

The poll results came as a surprise to Insight Manitoba co-founder Eric Stewart, he said.

"We didn't expect this much movement this soon in the election.... We think it's an indication of a trend," he said.

The poll also suggests province-wide, the PCs are still in the lead at 42 per cent; the NDP sits at 22 per cent; the Liberals at 15 per cent; the Greens at five per cent; and just two weeks away from the election, 16 per cent of Manitobans remain undecided.

Royce Koop, a political analyst at the University of Manitoba, said the dip in Liberal support is good news for New Democrats.

"If the Liberals' popularity keeps going down it will help both parties but it will help mostly the NDP," said Koop.

"The more the Liberal vote goes down in Winnipeg, the more the NDP is going to benefit from that and hold on to some of those seats that the Tories would have been able to pick up as a result of a split vote." 

As we near April 19, it will become more difficult for any party leader to turn voter opinion, Koop added.

"That includes Greg Selinger. It's getting harder for him to come back in the polls, and it includes [Rana] Bokhari, she's set a campaign narrative, a lot of these errors are cemented in the minds of voters," he said. 

'We're all about sample size'

Insight Manitoba is new to the provincial polling game, but its directors already claim to be a more reliable source for voting statistics in Manitoba than other polling companies.

"We're all about sample size," said co-founder Eric Stewart, adding the company also prides itself on its low margin of error and "qualifying questions" it uses to eliminate certain results for more accurate data.

"That's why we think it's better than what's out there."

Stewart, Gerald Denais and James Cook surveyed 4,592 people in the province in the most recent poll — significantly more than any other poll the CBC has reported on during this campaign.

Insight Manitoba was born out of dissatisfaction with the quality of polling done on a national scale leading up to the 2015 federal election, Stewart said.

All three men count themselves as Liberals; all three worked on Liberal member of Parliament Robert-Falcon Ouellette's campaign. (Stewart was Ouellette's campaign manager during the 2014 Winnipeg mayoral election.)

Cook is running Michelle Finley's provincial campaign for the Liberals in St. James. Stewart had been acting in an advisory role for Finley's campaign until recently.

As far as the optics of three Liberal-affiliated people putting out a poll that doesn't reflect well on that party, Stewart said the data speaks for itself.

"I'm confidant in the numbers we have and the numbers we presented. If our goal is to present accurate numbers and data people can rely on, I am happy about that — regardless of the results towards a party which I have been known to be affiliated with," Stewart said.

A probabilistic sample of the size used in Insight Manitoba's poll for Winnipeg would yield a margin of error of +/- 1.65 per cent, 19 times out of 20.

Manitobans head to the polls April 19.

With files from CBC's Chris Glover and Nelly Gonzalez