Emergency crews were called to the intersection of Pacific and Scott streets at about 10.30pm after reports of the incident.

Police said in a statement on Thursday morning the man "came off his bicycle after attempting to cross the tram lines, falling and sustaining head injuries".

Newcastle East resident Leah Audet was walking nearby with two friends when they heard a "thud".

"[We] turned around and ran towards him while I dialled 000," she told the Newcastle Herald.

"Fortunately a doctor was driving by and pulled over and started performing CPR."

The man, who was wearing a helmet at the time, was taken to John Hunter Hospital where he died, police said.

An investigation into the 51-year-old's death is ongoing.

Hunter cycling advocate Sam Reich, from Newcastle Cycleways Movement, said he was "shattered" to hear that a second cyclist had died on inner city roads in four months.

"I feel like we're getting nowhere and our warnings - ignored and even criticised by decision-makers - are now coming back to bite us," he said.

In the news:

"When are we going to wake up and realise we need a solution to these issues?"

There has been a run of bad crashes involving cyclists, resulting in serious injury or death, in Newcastle in the past nine months.

Brigitte Nilson, 57, died when she was involved in a crash with a turning truck at Perkins Street on the morning of March 20.

Meanwhile, the Newcastle Herald reported in November that Honeysuckle resident Nick van Veld came off his bike while trying to cross the light rail line at Scott Street.

His knee was broken in two places, he spent five days in hospital and had to wear a brace for about three months.

Only a month earlier, Grain Store owner Corey Crooks broke his right arm in three places when he crashed while crossing the light rail tracks on a bike on Hunter Street.

The state government's Newcastle Transport website has a list of safety tips for cyclists travelling near the light rail tracks.

But peak cycling body Bicycle NSW said on Thursday the advice for riders to cross the tracks at a 90 degree angle was not possible where Wednesday night's crash occurred.

"We need intersections to provide safe crossings for everyone," Bicycle NSW spokesman Bastien Wallace said.

"People who ride bikes and use wheeled mobility assistance need to be able to reach their destinations safely."

A Transport for NSW spokesperson said it would be "inappropriate" to comment on the incident at this stage, given police were investigating the man's death.

"Our sincere condolences and thoughts are with the gentleman's family, friends and colleagues at this time," the spokesperson said.

A Roads and Maritime Services spokesperson said the authority would not comment on the incident, but offered condolences to the man's family and friends as well as witnesses and people who went to his aid.

He pointed to a "comprehensive safety messaging campaign" conducted during the construction of the light rail network and in its early days of operation.

"The cyclist safety campaign was designed in consultation with the Newcastle Cycleways Movement and included school visits, distributing brochures and using media and social media channels," he said.

"Comprehensive signage alerting cyclists to their proximity to the light rail corridor has been in place since late 2018."

Newcastle light rail operator Keolis Downer declined to comment on Thursday.