Cameco Corp. has deferred planned uranium sales from its flooded Cigar Lake mine for up to seven years, putting further supply constraints on an already tight market and raising concerns the crucial project could be delayed even longer than expected.

The world's largest uranium producer said it has postponed deliveries of Cigar Lake uranium initially scheduled for this year to the end of those contracts and said other customer deliveries affected by the supply interruption will be put off for "a five- to seven-year period."

TD Newcrest analyst Greg Barnes said this may suggest a more protracted holdup in getting Cigar Lake into production than first thought. "This statement is likely, in our view, to provide further upward momentum behind the uranium price," Mr. Barnes said in a note to clients.

The massive Cigar Lake mine in Northern Saskatchewan filled with water in late October, quashing hopes it would begin producing uranium -- which is used as fuel in nuclear reactors -- by the end of this year.