The homelessness crisis in San Francisco has grown so bad that people are now sleeping at the city's airport.

Officials at San Francisco International Airport, (SFO), said they are encountering a surge of homeless people taking refuge there. Many are said to arrive in the middle of the night via BART trains south from the city.

Spokesman Doug Yagel told KTVU that staff are working hard to develop effective short and long-term solutions to address the issue.

Officials at San Francisco International Airport said they are experiencing a recent 'surge' of homeless people taking refuge there.

Over the past two years, airport duty managers and San Francisco police officers who patrol SFO claim official contacts with homeless people have tripled, according to figures obtained by the San Francisco Chronicle.

There were 1,139 such calls in February, or roughly 40 a day, compared with about 12 contacts daily in March 2017.

Officials claim that a large percentage of people arrive on the last BART train each night, which pulls into the International Terminal after 1.30 am and then clears out, with no return run to San Francisco.

The terminal is mostly empty when departing flights have ceased, and airport officials said the arrivals raise security concerns when this happens.

Yagel added: 'We might make SamTrans tokens available to them. We might, if they're eligible, transport them to a nearby homeless shelter, if BART is still running we can give them a token to a BART train.

'Ultimately we want to develop advocacy that finds the proper channels for these individuals.

Many homeless people are said to arrive at the airport in the middle of the night via BART trains south from the city. Pictured are homeless people just outside of the airport grounds

The terminal is mostly empty when departing flights have ceased

Video courtesy KRON

'So, we're starting to reach out to homeless advocacy in San Mateo County. We're looking to set up something with the city of San Francisco as well.'

While Yakel said the majority of the contacts with homeless people stem from the final train each night, BART officials disagreed.

They said possibly four or five homeless people are typically encountered each night at the airport, which is similar to other end-of-line stations like those in Richmond and Fremont.

Armando Sandoval, the BART police crisis intervention team coordinator, said officers typically find people at the end of line, often asleep.

A recent report found that 28,200 people in the Bay Area are experiencing homelessness, compared to 76,500 in New York and 55,200 in Los Angeles

San Francisco has the third-largest homeless population in the nation, behind New York and Los Angeles

Officials claim that a large percentage of people arrive on the BART train (pictured) which runs to the airport until 1:30am

'I think it’s typical of migrating homeless. It could be buses, trains or subway trains,' Sandoval said.

'They spend time on the trains and forget where they are and end up at the end-of-the-line locations.'

A report published last month by the Bay Area Council Economic Institute found San Francisco has the third-largest homeless population in the nation, behind New York and Los Angeles.

It stated that 28,200 people in the Bay Area are experiencing homelessness, compared to 76,500 in New York and 55,200 in Los Angeles.

The report also found that two-thirds of the Bay Area's homeless are living on the streets or in cars.

Other Bay Area transit agencies are encountering the same issue with homeless people seek shelter on late-night runs.

The Valley Transportation Authority’s overnight Route 22 bus line or 'Hotel 22'offers a warm, safe space for the desperate to sleep as the coach rumbles around Santa Clara County.