An environmental umbrella group wants Ottawa to reverse a decision to pull its funding, though the government says the move is necessary during a time of fiscal restraint.

The Canadian Environmental Network (RCEN) received notice Thursday that it would not receive $547,000 in core funding that the government had previously said it intended to provide.

Olivier Kolmel, the chairman of the organization's board of directors, said Ottawa did not give any warning that it would cut off its funding next year.

"If we would have had warning and we had known several months ahead of time, we could plan for some kind of transitional model, to move on to a different financial model," Kolmel told in a telephone interview on Friday morning.

The RCEN has existed for more than three decades and includes more than 600 member organizations from across Canada.

It has supported environmental groups with networking, communication and co-ordination services and helped the government arrange consultations.

Environmentalists denounced Ottawa's move, saying the decision to pull funding is part of a systematic Conservative campaign to weaken the green movement.

"Don't be fooled. This isn't about austerity. It's vindictive petty politics -- part of a systematic campaign by right-wing extremists to marginalize voices of the environment," John Bennett, the executive director of Sierra Club Canada, said in a statement.

With news of the abrupt funding change, RCEN is now scrambling to try to get Environment Canada to reverse its decision, while preparing for layoffs within the organization.

According to Kolmel, Environment Canada indicated in its notice to RCEN that it made its decision after conducting a review of the finances for grants and contributions within the government department.

A spokesperson for Environment Minister Peter Kent confirmed that the department would be pulling the RCEN funding.

"Environment Canada has decided not to enter into a contribution agreement with the Canadian Environmental Network this fiscal year," Melissa Lantsman told in an email on Friday.

"Responsible spending and sound management of tax dollars are important at all times. During difficult economic times, Canadians expect the government to be even more vigilant."

Lantsman said Environment Canada intends to move towards "a more direct use of web-based consultation" in future.

"The intent is to expand on these to not only provide comments on discussion papers, but to invite stakeholders to submit ideas or policy solutions on the Government's environmental priorities."

But Kolmel said that if the government cuts ties with RCEN, they will be losing out on a valuable resource that would be very costly to replace.

"We have been around for 30 years and we have millions of volunteer hours that have been given by our membership," said Kolmel.

Megan Leslie, the environment critic for the New Democrats, said the government cannot justify ending the funding for RCEN.

"The government has told RCEN that this decision is part of a cost-efficiency plan, but given the important role this organization plays, cancelling their funding will likely have expensive, long-term consequences," Leslie said in a statement.

"This decision just doesn't make sense financially, and it will endanger the health and sustainability of our environment."