Bob Menendez corruption trial begins hearing opening remarks

Watch: Key moments in US senator's corruption saga

A judge has barred a psychiatrist's testimony in the trial of a US senator charged with accepting bribes, including gold bars, in exchange for helping foreign governments.

US District Judge Sidney Stein denied the defence expert's testimony, saying that some of the doctor's sworn statements would be based on hearsay.

Senator Robert Menendez has pleaded not guilty to all 18 charges against him.

Opening remarks in the trial began on Wednesday.

Mr Menendez has been the US senator for New Jersey since 2006. He was also the top-ranking Democrat on the powerful Senate Foreign Relations Committee for more than five years, a position that gave him significant influence over US foreign policy.

Jury selection began on Monday and the criminal trial is expected to last six to eight weeks with Mr Menendez, 70, required to attend each day.

The defence was hoping to send Karen Rosenbaum, a psychiatrist, to the stand to testify that Mr Menendez stashed gold bars and envelopes of cash in his home as a "fear of scarcity" response to "intergenerational trauma".

Mr Menendez is the son of Cuban immigrants and he says his family faced having most of its savings confiscated by the Cuban government before they emigrated. His father was a compulsive gambler who failed to pay off his debts and later died by suicide.

Prosecutors objected to the proposed testimony from Ms Rosenbaum, doubting the scientific merit of the claims, and argued it was a tactic to gain sympathy from the jury.

On Tuesday, the judge barred testimony by Ms Rosenbaum, who had evaluated the senator, saying it would be "impermissibly based on inadmissible hearsay".

Mr Menendez has been charged with 18 criminal counts, including bribery, extortion, wire fraud, obstruction of justice and acting as a foreign agent.

Investigators executing a search warrant at Mr Menendez's home in September found more than $480,000 (£380,000) in cash stuffed in envelopes and coats, and 13 gold bars worth over $100,000.

Agents also found other apparent gifts, including a Mercedes-Benz and a range of home furnishings.

Prosecutors say the gold, cash and other luxury items discovered were part of a scheme to aid the government of Egypt.

The justice department also alleges Mr Menendez had accepted bribes to use his influence to benefit Qatar.

Mr Menendez is on trial with Fred Daibes, a New Jersey real estate developer who allegedly delivered the gold and cash to the senator, and businessman Wael Hana, who allegedly brokered a deal between Mr Menendez and the Egyptian government. Both Mr Daibes and Mr Hana have also pleaded not guilty.

Mr Menendez's wife, Nadine Arslanian Menendez, also faces bribery and corruption charges to which she has pleaded not guilty. She is being tried separately.