RIO DE JANEIRO, Sept 8 (Reuters) - Brazil's largest oilworkers union federation on Tuesday renewed its threat to strike at any time against state-run oil company Petroleo Brasileiro SA after having recently let other strike warnings lapse.
The union, known as FUP, hopes to keep Petrobras, as the company is known, off guard by meeting the legal notification requirements for a strike while putting off any actual start to the work action until it considers a start convenient, a press spokeswoman said in an interview.
As required by law, FUP must inform Petrobras of strikes at least 72 hours in advance. The union told Petrobras on Friday that it is prepared to start a strike by Wednesday.
Previous notifications since late August have passed without any strike action.
The spokeswoman for the union said it plans to keep filing strike threat notifications on a daily basis until a strike begins, the company meets their demands or it reaches agreement on a new collective contract agreement.
The union, which is in contract talks with Petrobras, has threatened to strike over the heavily indebted company's plans to sell $15.1 billion of assets by the end of 2016.
Another motive for the threatened strike is its objection to a bill in congress that would allow Petrobras to opt out of investments and leadership of expensive new developments in a giant offshore area known as the Subsalt Polygon.
The Polygon may contain 176 billion barrels of undiscovered oil and equivalent natural gas according to Brazil's National Institute of Oil and Gas at Rio de Janeiro-State University, enough to supply all the world's current needs for five years.
The polygon, which makes up nearly all undeveloped areas in the Campo and Santos offshore basins near Rio de Janeiro, contains giant new resources trapped by a layer of mineral salts deep beneath the seabed.
Petrobras said on Friday that it would make a new proposal to the union on Thursday. Company officials were not immediately available for comment on Tuesday. (Reporting by Jeb Blount Editing by W Simon)