Ottawa says China not the only potential investor in Canada's oil

* Canada says needs C$650 billion investment in energy

* United States, Norway, France also investing

* Canada now examining CNOOC bid for Nexen

By Jim Morris

VANCOUVER, Sept 7 (Reuters) - China is not the only possible source of the massive investment that Canada needs to develop its oil-rich tar sands and other energy assets, Natural Resources Minister Joe Oliver said on Friday.

Cash-rich Chinese companies are showing an increased interest in Canadian oil and gas and Ottawa is currently reviewing a $15.1 billion takeover bid for Canadian oil company Nexen Inc by Chinese state-owned firm CNOOC Ltd .

The CNOOC bid is causing political tensions, since some members of the governing Conservative Party are uneasy about the idea of a state-owned Chinese company buying assets in Canada.

Oliver -- who says Canada's energy patch needs at least C$650 billion ($665 billion) in investment over the next decade -- dismissed the suggestion that China was the sole nation with access to such sums.

"China is not the only source of capital in the world. We have had investment from the United States, more from the United States than any other country," he told reporters in Vancouver.

That said, if the CNOOC bid is approved, Chinese investment in the tar sands and Canadian energy assets in the last year alone will have hit more than C$20 billion, far more than any other country over the same period.

Oliver cited France, the Netherlands, Japan and Malaysia as other investors.

"We are welcoming and our regulatory system does not discriminate against foreign companies once they arrive. So Canada is a destination for a lot of foreign capital. We want to continue to make it that way," he said.

Oliver said his comments should not be taken as a hint of whether Canada will approve the CNOOC bid or not.

Prime Minister Stephen Harper said on Thursday that Ottawa would study CNOOC's approach particularly closely because the deal is large and the company is a state-owned enterprise.

Harper went to China in February to promote Canadian oil. Canada exports almost no crude to China and will not be able to do so until more pipelines are built from the Alberta tar sands to ports in British Columbia on Canada's Pacific Coast.

There is increasing opposition in British Columbia to the idea of building pipelines, which critics say will mean an increase in tanker traffic and the chances of a catastrophic spill.

One of the proposed pipelines would be built by Enbridge Inc , which was blasted by U.S. regulators in late July over an "absolutely unacceptable" spill in the U.S. Midwest.

Oliver promised Ottawa would put in place "world-class" pipeline and tanker safety measures before any project began.

"We are not going to go ahead with a project that would jeopardize the safety of the environment, or the safety of British Columbians," he told reporters.

Oliver noted that oil tankers had been moving safely along Canada's West Coast since the 1930s.