CANADA MAY MONITOR STEEL SHIPMENTS Canada may begin monitoring steel flowing in and out of the country to determine if any steel is being illegally "trans-shipped" to the U.S., senior government trade officials said. The officials, asking not to be identified, said the government will investigate an industry contention that steel imported from countries such as South Korea and Taiwan is being diverted to the U.S. and ultimately exasperating concerns about the level of Canadian exports south of the border. But the senior officials, asking not to be indentified, said that despite intense pressure from the Reagan Administration, Ottawa was not considering any kind of formal limits on Canadian shipments to the U.S. "In a sense what I hope we are doing is buying some time," said one official who claimed Canadian companies were "fair traders" in the big American market. If approved by the Canadian cabinet, the officials said a monitoring system will be established in the next three or four months. "I guess if we find trans-shipment is a problem, we would have to do something about it," said a trade official. Canadian steel shipments to the U.S. have risen to 5.7 pct of the U.S. market in recent months, almost double the level just two years ago. The increase in Canadian shipments comes at a time of growing anger in the U.S. over rising steel imports from several countries in the face of a decline among domestic steel producers. Some U.S. lawmakers have proposed Canada's share of the American market be limited to 2.4 per cent. The Ontario Government has urged Ottawa to require foreign companies to obtain permits to import steel into the country. Currently, import licences are required only for carbon or raw steel, which makes up less than half the steel market. Canada exported two billion Canadian dlrs worth of steel in 1986, while importing 944-mln dlrs worth of the product in the same year.