Dissension is growing among Manitoba's New Democrats about Premier Greg Selinger's ability to lead the party into the next provincial election, with one current cabinet minister suggesting he should reflect on the latest polls.

Stan Struthers, who is currently minister of municipal government, told CBC News that the premier should think about the polls, which suggest the party is losing popularity, and do what's best for Manitobans.

"We've had a series of polls that have indicated that the people of Manitoba are very concerned about the way that the PST decision was made and how it was handled," Struthers said late Monday.

Stan Struthers - Oct. 27, 2014

Stan Struthers, who was Manitoba's finance minister when the provincial sales tax was raised from seven to eight per cent in 2013, said on Monday that the PST increase was not unanimously supported by government. (Kiran Dhillon/CBC)

"I believe the premier will take a look at all of that and he'll make a determination. He'll reflect on all the information that he has, and I think he does have a decision to make."

Struthers would not say if he wants Selinger to consider stepping down. He said he's confident the premier will make the right decision.

"All I've asked of the premier is that he take a look at all of the information, reflect upon it, and then make a decision himself," Struthers said. "That is his decision to make."

Struthers was finance minister when the provincial sales tax was raised from seven to eight per cent in 2013.

The PST increase was not unanimously supported by the government, Struthers said late Monday. However, he wouldn't say what advice he, as finance minister, gave to the premier on the matter.

Some cabinet ministers said they are fully supporting the premier and don't think he should step down.

Education Minister James Allum called Selinger a man of integrity and said he has made some difficult decisions for the benefit of Manitobans, such as raising the PST to help pay for infrastructure.

Others, like Jennifer Howard, declined to comment on Monday.

Former cabinet minister speaks out

Former cabinet minister Becky Barrett, who was the party’s director of organization during the 1980s and remains on the executive, stopped short of suggesting Selinger should resign, but noted that it's an option.

"I'm speaking out because I think it's critically important that things change," she said.

What those "things" are, she didn't say. However, she said Selinger "has a very difficult decision to make and he has to make it very quickly."

"I think his decision has to be about what is the best thing for the people of Manitoba, what is going to make the people of Manitoba regain their faith in the NDP and to remember the good things that the NDP has done over the past 15 years," Barrett said. "So far the premier hasn't been able to make that trust happen again."

Barrett noted there have been several poll results the past year showing the party is losing popularity.

'We haven't been able to get beyond the concerns raised by Manitobans about their lack of trust in the leader and their feeling that they were betrayed by him.' - Becky Barrett

"That shows that there's a huge lack of trust and commitment to him and the party and I think that he has a decision to make about how he goes forward," she said. 

With only a year and a half to go before the next election, people within the party are getting worried, she added.

"I know that people in the party are very concerned and I think it's a legitimate concern because you can't have over a year of really bad poll results that are not only not getting better, but are actually seeming to get worse."

One of the biggest concerns is the backlash from Selinger's about-face on the provincial sales tax (PST). He said in the 2011 election campaign that he would not increase the PST to eight per cent from from seven per cent but then did exactly that in July 2013.

"In that year-and-a-half, things have gone from bad to worse for the party and the leader. The polls have been showing consistently that as a party we are losing and the premier has lost the trust and confidence of the people of Manitoba," Barrett said.

"I think it's to the point now where it's getting to be critical."

NDP workers were out campaigning for several candidates during the recent civic election in Manitoba and they heard loud and clear the public was not happy, Barrett said.

"I'm concerned that in the last 18 months the issues have been largely due to the PST and that we haven't been able to get beyond the concerns raised by Manitobans about their lack of trust in the leader and their feeling that they were betrayed by him when he went back on his word not to raise the tax," she said.

"They have become more and more convinced that he lied to them that he betrayed them. He hasn't in the last 18 months been able to explain adequately the reason for his decision and consequently we haven't been able to regain the trust of Manitobans and they're starting to look elsewhere."

NDP responds

CBC News requested comment from the premier on the matter and was sent the following statement from a spokesperson:

"Premier Selinger remains focused on the job he was elected to do  delivering on the priorities of Manitoba families, creating jobs and opportunities for young people, growing our economy."

Rosann Wowchuk, a former NDP cabinet minister and current co-chair of the party's re-election planning committee, said there's always some dissension within any party.

And while she admits there is concern, public support for the party remains strong.

"Of course, poll numbers always concern you when you're doing this kind of thing,” she said. “[But] as I said, it's been a very successful year raising money this year for the party."

As for Selinger stepping down as leader, Wowchuck said that's not likely.

“He has been elected as leader of the party and he's going to continue to stay on as leader of the party. He's not given any indication to me that he is planning to leave," she said.

Political scientist Raymond Hébert said there is always some grumbling when a party has been in power for a long time, but he said it shouldn't be enough for Selinger to step down.

"We're not seeing a full-blown revolt against Greg Selinger. That's obvious. There will have to be a lot more water under the bridge before ... I think the situation gets serious," he said.

"He probably has some work to do in massaging his caucus and his cabinet, but I think anonymous comments and sources aren't sufficient."

A lot can happen between now and the provincial election for Selinger to turn things around, Hébert added.