Some 450 people in Brighton and Hove are HIV positive but do not realise it, the Conservative MP for Hove told the House of Commons.
Mike Weatherley said: “The government and local services must do everything that they can to bring the number down.
“I am determined to do what I can to support the NHS at the local level in this task.”
He said that more should also be done to tackle late diagnosis as this often meant that patients suffered more complications than those who had a prompt diagnosis.
Mr Weatherley also reminded fellow MPs that HIV did not just affect young men on the gay scene or people in or from Africa.
Not only did it also affect white middle-aged and older straight men and women but 26 per cent of all those who live with HIV in Britain have not had their condition diagnosed.
He was speaking in a debate on World Aids Day on Wednesday.
He said: “Now is the time, while we are focusing on public health and while we are worrying about public finances, to take action to tackle late diagnosis and undiagnosed HIV.
“I am proud to say that people in Brighton and Hove are not sitting back waiting for someone to come up with a solution but are already working hard to tackle the problem.
“There have been two pilot studies in our area looking into ways of reducing undiagnosed HIV, using clinicians in the area.”
He called for GPs and surgery staff to be given better training across the country.
He said: “In Hove and in Brighton we have some of the most HIV-aware clinicians in the country, and our specialists are among the best in the world.”
He added: “However, we must not be complacent.”
