His announcement on Saturday came as all but two beaches in Vancouver reopened after officials said water and sand samples showed no harmful levels of oil.
Mulcair said a recent toxic fuel spill in English Bay is a "wake-up call" and Conservative cuts are threatening British Columbia's coast.
"This is not about ideology anymore. This is about common sense. This is about protecting people, about protecting ecosystems," Mulcair told reporters gathered at English Bay.
"This is a dangerous precedent Mr. Harper's set. But what we've learned is we don't even have adequate response time for a moderately sized oil spill."
The MV Marathassa dumped at least 2,700 litres of bunker fuel into English Bay last Wednesday and quickly spread to beaches along Stanley Park and North and West Vancouver.
All Vancouver beaches except for Crab and New Brighton park were reopened on Saturday, but beachgoers were warned to avoid contact with any small amounts of remaining oil. West Vancouver beaches are still closed.
The Canadian Coast Guard has faced harsh criticism for its response. A recreational boater noticed the spill at about 5 p.m. Wednesday but an oil-absorbing boom was not secured around the vessel until 5:53 a.m.
Mulcair echoed the comments of former Kitsilano Coast Guard commander Fred Moxey, who has said the station — located next to English Bay — would have been able to respond to the spill in "minutes."
The federal government closed the base in 2013 as a cost-cutting measure.
New Democrat MP Fin Donnelly will introduce the motion on Monday. It will also demand a recently closed marine communication and traffic centre in Ucluelet be reopened, and call for a stop to planned closures of similar centres in Vancouver and Comox.
The Coast Guard has been adamant that the Kitsilano base was a search-and-rescue location that was not equipped to handle this type of spill.
"Thomas Mulcair is clearly misleading British Columbians to serve his political agenda," Sophie Doucet, a spokeswoman for Fisheries Minister Gail Shea, said in a statement.
Metro Vancouver officials have stated that the government's plans to consolidate various marine communication and traffic centres will not compromise ship safety, Doucet added.
Mulcair said that if an NDP government is elected this year, it will reopen the Kitsilano Coast Guard. Justin Trudeau's Liberal party has made the same promise.
North Vancouver's Squamish Nation demanded on Saturday to play "priority-one role" in future spill responses — meaning it would be called first, on the same priority list as the city and the province.
Chief Ian Campbell said the federal government has a long way to go before it meets a commitment made last year to have a "world class" tanker safety system including in aboriginal communities.
"The English Bay heavy oil spill has the potential to damage our sensitive marine habitats in our waters. And the cleanup response can hardly be called 'world class.' In fact, the response was inept and sluggish," he said in a statement.
The Department of Fisheries said the Squamish and Tsleil-Waututh First Nations have representatives on site at the incident command post and have discussed their concerns with Coast Guard officials.
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