Federal New Democratic Party Leader Tom Mulcair warned Rothesay residents about the potential problems with shale gas exploration during a byelection campaign stop in the southern New Brunswick town on Sunday.

Mulcair held a public rally with New Brunswick NDP Leader Dominic Cardy on Sunday to boost his chances in the June 25 byelection.

Cardy is trying to win the seat vacated by former Progressive Conservative MLA Margaret-Ann Blaney, who left politics to take the high-paying position as president and chief executive officer of Efficiency New Brunswick.

Mulcair used the rally to criticize the province's shale gas policies, suggesting that Rothesay's drinking water could be threatened if companies went forward with hydraulic fracturing, which is also known as hydro-fracking.

"It's a beautiful pristine source of drinking water. That would be put in danger with fracking. Look at the American experience. Look at what's happened in states like Pennsylvania. People have to be made to understand that this is a false choice," Mulcair told the rally.

The New Brunswick government is proposing 116 changes to the regulatory framework that oversees the oil and gas industry.

The second in a series of town hall meetings to review that plan is in Durham Bridge on Monday.

The federal NDP leader said natural gas companies do not want to answer tough questions about shale gas exploration and hydro-fracking.

"Well, here's one tough question: If you think that your method of getting to that gas is safe, why won't you reveal the contents of the fracking fluid?" Mulcair said.

In New Brunswick, the provincial government has committed to requiring, "mandatory disclosure of fracture fluid additives."

Mulcair's views on resource development have come under fire in recent weeks.

Preston Manning, the former Reform Party leader, called Mulcair "hypocritical" for "preaching" to Alberta while turning a blind eye to the environmental cost of producing energy in Quebec. Manning's comments came during an interview that aired Saturday on CBC Radio's The House.

Mulcair has drawn the ire of the federal government and some western premiers for his thoughts on oilsands development.

The federal NDP leader has said the Canadian dollar is being held "artificially high" by the oilsands causing the economy harm in other parts of the country.

The Mulcair rally was attended by a small crowd of NDP supporters.

Cardy was an early supporter of Mulcair when the Montreal MP announced he was running for the federal party’s leadership after the death of Jack Layton.

Mulcair said other federal NDP members would be coming to Rothesay in the coming weeks to help Cardy.

The NDP has not held a seat in the legislature since 2005 when former party leader Elizabeth Weir resigned to become the president and chief executive officer of Efficiency NB.

Cardy announced that he would run in the Rothesay byelection shortly after Premier David Alward announced the date. There are five candidates in the race to replace Blaney.

The Progressive Conservatives are fielding Hugh John (Ted) Flemming III and John Wilcox, a retired police officer, is running for the Liberals.

Sharon Murphy will be running in the riding again for the Green Party and Marjorie MacMurray will be on the ballot as an Independent candidate.

Patronage attacked

Cardy told a crowd in Rothesay on Sunday the province can no longer afford the patronage and broken promises offered by the Progressive Conservatives and Liberals. (CBC)

While Mulcair used the Rothesay rally to blast the provincial government on its shale gas regulations, Cardy continued to hammer the Progressive Conservatives and the Liberals on patronage.

Blaney’s appointment to Efficiency NB has been criticized as patronage and several prominent Progressive Conservatives, including Finance Minister Blaine Higgs and Flemming have not endorsed the appointment.

"We cannot build a strong province that our children deserve without talking about the culture of patronage that is holding New Brunswick back. This is an addiction that our province can no longer afford," Cardy said.

The NDP leader is proposing what he calls his Rothesay charter, which would ban hiring based on political affiliation, except for political staff.

Cardy’s proposal, which would need to be endorsed by the Progressive Conservatives and the Liberals, would also lay out a new hiring procedure for chief executive officers of Crown corporations.

Cardy told the Rothesay crowd the Tories and the Liberals have squandered the province’s development through a litany of broken promises and patronage appointments.

"Our Liberals, our Conservatives they were too often lazy and too often careless and instead of investing in our province's future they gave it away with every patronage appointment, every broken word and every ridiculous promise made, they gave it away," Cardy said.

"There is no perfection in this world but there is a constant fight to do better. You have to decide whether to engage in that fight, you have to decide whether to try to make things better. The New Democrats, we have made that decision."

Mulcair said on Sunday that he would like to see New Brunswick voters embrace the NDP as a legitimate alternative to the two traditional parties. He pointed out how many Canadian voters turned to the NDP in the recent federal election, making it the Official Opposition.

"After over 100 years of alternating between Liberal patronage and Conservative patronage, New Brunswickers now have a choice," he said.