TORONTO (AP) _ A thousand blue boxes containing a new daily newspaper have appeared on Toronto street corners in what promises to be a spirited battle for Canadian business readers and advertisers.

As of Tuesday, the tabloid Financial Post, partly owned by Toronto press baron Conrad Black and the Financial Times of London, invaded ground now occupied by the weighty Report on Business section of the Toronto Globe and Mail, Canada's national newspaper with a daily circulation of 326,000.

Until now, the 81-year-old Financial Post has been a weekly broadsheet with a paid circulation of 185,000.

Black, owner of the London Daily Telegraph, felt there was an untapped market for a Canadian daily exclusively devoted to business and interested the Financial Times of London in becoming a minority partner.

''As long as the Post produces a good product, there's no reason why it shouldn't be successful,'' said Black, whose company owns 128 newspapers and Canada's influential Saturday Night magazine.

''I don't think the Globe was covering the entire business field, so there is an opportunity for a more interesting paper.''

Black's company, Hollinger Inc., paid 6.9 million Canadian dollars, or $5.3 million, for a 15 percent stake in the newly established Financial Post Co.

The Financial Times acquired 25 percent of the new tabloid for 11.5 million Canadian dollars.

The majority owner of the new paper, with 60 percent, is the Toronto Sun Publishing Corp., which produces lively tabloids in Toronto, Edmonton and Calgary and will print the daily Post at its Toronto plant.

The first press run was 100,000 but the start-up circulation goal is 50,000. The paper will appear Tuesday to Friday with a weekly edition on Saturday.

''We're not expecting a profit in year one but there's a chance of breaking even in year two,'' said publisher Neville Nankivell.

The first edition ran to 96 pages, 60 of them ads, and the newsstand price was 35 Canadian cents, compared with 25 Canadian cents for the Globe.

''The mix looks really good,'' said one first-day reader, executive Jane Lesslie of the Royal Bank of Canada. ''Many people at the bank have said they'd like to see a Wall Street Journal for Canada.''

Another rival, the weekly Financial Times of Canada, has had a recent facelift, and even the Toronto Star - Canada's biggest selling popular paper at 517,000 copies a day - acknowledged the potential impact Tuesday by publishing a 16-page supplement on stocks and investment.