Veteran British Columbia MP Nathan Cullen says he won’t run to succeed Tom Mulcair as the leader of the federal New Democrats, preferring to concentrate on electoral reform and climate change.

Cullen, first elected in 2004 to the sprawling northwestern B.C. riding of Skeena−Bulkley Valley, ran against Mulcair in the party’s 2012 leadership race, ultimately coming in third behind runner−up Brian Topp.

He said his decision to forgo another run came after much thought and discussion with family friends and supporters.

Three factors came foremost: "What is best for me and my family, what is best for the people I represent in northwestern British Columbia and what this party that I love so much needs and deserves right now," he said.

Cullen came to the conclusion he has other work to focus on.

"One aspect of this decision today — and it’s a good aspect for me — is that it allows me the total commitment to the process ... on helping create and form with Canadians a new electoral system," he said.

He also cited the need to work on climate change.

The party has opted for an extended leadership race to replace Mulcair and expects to choose a new leader sometime in the fall of 2017, with the nomination period set to begin next month.

Mulcair was flatly rejected as the party’s long−term leader at a convention in Edmonton last month, when more than half the delegates voted for a leadership race.

In order to run, hopefuls will be required to provide a registration fee of $30,000 while the spending cap has been set at $1.5 million.

The party suffered a sharp rejection in the October election, losing more than half its seats and dropping back to third party status.

Cullen said, though, that will change.

"We will be ready again to form government again in just a few short years," he said.