Jan 9 (Reuters) - A convicted former outside lawyer for collapsed commodities brokerage Refco Finance Holdings LLC is entitled to a new trial because he was denied his right to be present at every stage of his trial, a U.S. appeals court ruled on Monday.

Joseph Collins, formerly a lawyer at Mayer Brown LLP, was convicted by a New York federal jury in July 2009 of conspiracy, securities fraud and wire fraud for his role in a $2.4 billion fraud that caused the collapse of Refco in 2005.

Collins' appeal stems from difficulties that arose between two jurors at the trial on the fifth day of deliberations.

The next day, the foreman sent a note to U.S. District Judge Robert Patterson saying that one juror had attempted to barter his vote and refused to deliberate.

In Monday's written ruling, a three-judge panel on the 2nd U.S. Circuit Court of Appeals said that Patterson did not share the contents of the note or seek counsel's input before interviewing the accused juror.

"During the interview, the court gave the juror what amounted to a supplemental instruction, emphasizing the importance of resolving the case," the ruling said. "This sequence of events deprived Collins of his right to be present at every stage of the trial.

"Because the deprivation was not harmless, we vacate and remand for a new trial."

A spokeswoman for the office of the Manhattan U.S. Attorney, which prosecuted the case, declined to comment on the ruling.

One of Collins' lawyers, William Schwartz of Cooley LLP, said in a statement: "After this long fight, we are very gratified by the Court of Appeals' decision."

Collins was found guilty of a broad conspiracy in a scheme in which both the former president and the former chief executive officer of Refco are serving prison terms. He was sentenced to seven years of imprisonment in January 2010 but has been free on bail pending the appeal.

The cases are USA v Collins, U.S. District Court for the Southern District of New York, No. 07-01170 and No. 10-1048-cr in the 2nd U.S. Circuit Court of Appeals in New York.

For the USA: Katherine Failla, Christopher Garcia and Justin Weddle of the U.S. Attorney's Office.

For Collins: Jonathan Bach, William Schwartz, Reed Smith and Jason Koral of Cooley. Kathleen Cassidy who was also on the Cooley team is now with Hafetz Necheles & Rocco.

(Reporting by Grant McCool)

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