The coroner at the inquest of Jean Charles de Menezes said today he would accept a majority verdict.
The 11 jurors have been deliberating for four days since Sir Michael Wright ruled out unlawful killing.
After the jury asked the coroner whether a unanimous decision was still necessary, he told them he could now take a verdict if at least nine of the 11 jurors agreed on every verdict.
Mr de Menezes, 27, was shot dead by police marksmen at Stockwell Tube station in south London on July 22 2005 after being mistaken for failed suicide bomber Hussain Osman.
The jurors have been told to cast aside any emotion in deciding between a lawful killing verdict or an open verdict.
They must also answer a questionnaire.
Sir Michael told the jurors they should "do their best" to be unanimous in answering the 13 questions in reaching their verdict.
But he added: "However, if you cannot manage to achieve complete agreement, the time has come when I'm now able to accept decisions from you on each of these matters where at least nine of you are agreed."
He told them there would be further directions tomorrow if they fail to reach a decision this afternoon.
Sir Michael previously took the unconventional step of issuing a "questionnaire" relating to the circumstances surrounding the incident.
After choosing between lawful killing or an open verdict, the jurors must decide:
* Did officer C12 shout the words "armed police" at Mr de Menezes before firing?
* Did Mr de Menezes stand up from his seat before he was grabbed in a bear hug by officer Ivor?
* Did Mr de Menezes move towards C12 before he was grabbed in a bear hug by officer Ivor?
The jurors will then rule whether a string of additional factors - including identification, photographs, communications and orders issued from the control room at New Scotland Yard - caused or contributed to the death of Mr de Menezes.
The inquest at the Oval cricket ground in south London has heard from 100 witnesses, including the two firearms officers who shot dead the electrician.
Last week the coroner told jurors to "ignore" a courtroom protest by family members.
Minutes before the jury was sent out to consider its verdict last week, three of Mr de Menezes's cousins stood up and unveiled T-shirts displaying the message: "Your legal right to decide - unlawful killing verdict."
The Menezes family's legal team, led by Michael Mansfield QC and his junior Henrietta Hill, was absent from court as the coroner completed his summing-up.Reuse content