The City of Vancouver has joined the growing list of groups asking the courts to halt the Trans Mountain Pipeline expansion project.

In the legal application that was filed in Vancouver on Friday the city is asking the Federal Court of Appeal to stop the National Energy Board from taking any action that would allow the project to move forward.

The city argues the National Energy Board failed to properly assess "whether the project is required by public convenience and necessity." when it recently approved the project with a number of conditions.

It also argues the NEB failed to conduct a proper environmental assessment of the project, including the full scope of  associated greenhouse gas emissions.

The legal action is just one of many challenges the controversial pipeline project is facing.

Over the weekend lawyers for the Living Oceans Society and the Raincoast Conservation Foundation said they have filed a judicial review, arguing the NEB did not take into account the impact the project would have on the endangered southern resident killer whales.

And earlier this month the Squamish Nation launched its own judicial review of the board's recommendation, arguing the NEB did not fulfil its obligation to consult with the First Nation about the project.

Kinder Morgan wants to triple the capacity of its existing pipeline from the oilsands near Edmonton to Burnaby, B.C., thereby increasing the number of tanker ships in the area seven-fold.

Following a second federal review, the federal Liberal government has said it expects to make a final decision on the $6.8-billion project in December.