Vancouver's new convention and exhibition facility is scheduled to be completed next April. (CBC)

B.C. Premier Gordon Campbell says he's confident that the new convention centre in Vancouver will pay for itself even though it is about $400 million over budget.

Campbell said on Thursday that the Vancouver Convention & Exhibition Centre, scheduled to complete next April, is expected to generate $2 billion with the 159 conventions it has booked so far.

"This convention centre will pay for itself in a very short order. It will be a strong economic engine," he said.

The current budget for the convention centre is $883 million, about $400 million more than originally budgeted.

Rick Antonson, president of Tourism Vancouver, says staff are keeping close contact with clients to secure future bookings at the convention centre. (CBC)

The convention business in Vancouver faces grave challenges to drum up bookings in the global financial meltdowns, said Rick Antonson, president of Tourism Vancouver.

Antonson said the one grouping of conventions by professional associations, which are usually long-term bookings, is still "very active" and has booked facilities at the new convention centre up until 2015 or 2016.

But the other grouping of conventions by the corporate sector is less predictable, he said.

"It gets a lot more tentative. They make decisions closer in to the dates they need the facilities," Antonson said Thursday.

"It is rare that conventions get cancelled … the important thing for the Vancouver convention business now is to stay close to our clients. We are in almost daily contact with people who are bringing in future conventions to Vancouver."

Some components not included in current budget: critic

New Democrat MLA Harry Bains said Thursday some other components of the new convention centre have not been factored in the already overrun budget.

One component is a project to connect the new centre to the neighbhouring old convention centre.

"The numbers I heard was about 30 million dollars at one point," said Bains, the opposition critic for the Olympics and sport.

"Whether the government will argue that it's still within the $883 budget remains to be seen," he said. "If someone says it's $1 billion or over, it will not surprise me a bit."

The premier said British Columbians shouldn't worry.

“There's a tendency to look at one side of the equation and not both sides,” Campbell said. “The other side of the equation is that we already have $2 billion of economic activity.”