Birmingham could be facing a major outbreak of tuberculosis (TB) within five years if the city fails to keep track of how quickly the city's immigrant population is growing, a health watchdog has been told.

Dr Chris Spencer-Jones, director of public health for South Birmingham Primary Care Trust, issued the warning as he addressed the city council's health overview and scrutiny committee.

He spoke out after the committee heard a set of "muddled" figures presented by Alan Randall, the council's lead officer on asylum seekers and refugees, who claimed "up to 100,000" people had settled in the city since 1997.

Of those, 35,000 had been granted permission to stay in the UK, with a further 20,000 coming over from EU countries, and "about 20,000" were of Somali origin. But question marks remained over the exact number of immigrants who come into Birmingham each year, how many brought over relatives and how many failed asylum seekers remained in the city.

Responding to Mr Randall's claim that 100,000 was a "big, but not overwhelming" figure, Dr Spencer-Jones said: "When does this become overwhelming, because in the health sector there's already been a very big impact from the immigrant sector, particularly in cases of HIV and TB.

"I do think we've got to become aware that this is going to have consequences, a lot of it good, but in health terms, do we know this is being dealt with properly?

"We could be incubating TB, particularly in the Somali community, and any downturn in the economy and public health could lead to an outbreak of TB in Birmingham within the next five years."

Methods to vaccinate children against the disease have recently been changed. Instead of all youngsters being given a BCG jab at 13, babies whose parents, grandparents or immediate relatives come from or regularly visit countries where TB is endemic, are actively inoculated.

Dr Spencer-Jones added: "TB is entirely treatable and we will have cases in the UK and Birmingham, with most occurring in Somali communities, but to know how prevalent that may be we need to know how many potential cases we have here.

"But these figures seem at best to be woolly, and to know the risk of any potential outbreak we need to know how big this population is."

Coun Deirdre Alden (Con Edgbaston), the committee's chairman, said: "This is a massively complicated issue which also impacts on education and housing, as well as health services across the city.

"I find it incredible that nobody really knows what's going on, even the experts - that seems to have been the conclusion of this meeting.

"In looking for clarity all we've discovered is that the system is totally muddled.

"It appears that this is a mess, but what concerns me most is this could be just the tip of the iceberg, particularly with talk of a possible TB epidemic."

Councillors had met to start an eight-month review of new migrant communities, their needs and how those impact on public services.

It is thought the cost of housing and supporting the migrants runs to "about #3 million a year", but Mr Randall claimed these communities were "actually very tiny compared to the national picture."

The number of unsuccessful applicants receiving short-term support has almost doubled in the eight months between November 2006 and last July, from 622 to "about 1,100", according to Mr Randall.

Many are from Iraq, Iran, Somalia and Afghanistan which make return difficult if not dangerous.