BRUSSELS, Aug 12 (Reuters) - U.S. life sciences company Illumina Inc on Thursday deplored EU antitrust regulators' decision to suspend temporarily their investigation into its planned purchase of Grail Inc, saying that the cancer test maker was crucial to patients.

The European Commission hit the pause button on Wednesday while waiting for Illumina to provide requested data, an EU filing showed.

The EU executive, which had previously set a Nov. 29 deadline for its decision on the deal, will announce a new deadline once it has received the information, in line with its policy.

Illumina was not happy with the EU halt but said that it was confident that the EU investigation would resume shortly and the deal ultimately approved.

"We are disappointed that the EC has chosen to delay its review of our re-acquisition of Grail given the importance of bringing Grail's life-saving test to as many patients as possible as quickly as possible," General Counsel Charles Dadswell said in a statement.

"We continue to work around the clock to meet the EC’s substantial demands and have already produced more than one million documents after receiving the EC's document request only 10 days ago," he said.

The EU competition watchdog last month warned that the deal could restrain innovation which could require Illumina to offer concessions to address its concerns.

The $8 billion cash-and-stock deal for startup Grail will see Illumina buy out investors including Amazon founder Jeff Bezos to regain control of a company it spun out five years ago. (Reporting by Foo Yun Chee; Editing by Susan Fenton and Chizu Nomiyama)