The National AIDS Trust has launched a new fundraising appeal in a bid to increase individual donations by tens of thousands of pounds.
The charity said it only received £2,500 in individual monthly donations last year and hopes to raise this to £25,000 in the next 12 months.
It is targeting gay men to increase their donations in the run-up to Pride.
Chief executive Deborah Jack said the charity was in a “very difficult economic climate” and is one of the few national organisations focusing solely on HIV.
NAT is far smaller than the other main HIV and sexual health charity Terrence Higgins Trust (THT).
Last year, NAT raised £967,506 and spent £937,704, compared to THT which raised £18,019,000 and spent £18,026,000.
THT has centres around the country offering support services and has broadened its remit to sexual health, while NAT focuses on lobbying and policy.
The news follows the announcement Crusaid is to merge into THT, but NAT says it is not in financial trouble.
Ms Jack said: “I appreciate everyone is feeling the pinch; but with more gay men than ever before living with HIV and high-rates of new infections it is even more important that an independent charity is working to keep HIV on the agenda in the UK.
“Many other charities in the sector have broadened their remit to include the whole of sexual health and now NAT is one of the few UK national charities focused solely on HIV.
“Often NAT works behind the scenes lobbying MPs and fighting to ensure the rights of gay men with HIV are on the agenda and campaigns to prevent HIV and promote testing are not sidelined.
“We need to get better at telling people about our vital work so that we can ensure it continues.”
An NAT spokeswoman told PinkNews.co.uk: “We’re not in financial trouble.
“But with the changes in the sector, we are aware that the next 12 months will be difficult.
“We want to highlight the fact we are focused on HIV, especially in the run-up to Pride.
“It sounds like a massive amount but we only need 200 people to sign up to pay £10 a month.”
The spokeswoman could not say what might happen if the target was not reached.
Instead, she said that the drive was about “building a support base” for the charity if it failed to secure any of the grants it applies for yearly.
This week, Crusaid, an HIV charity which hands out support grants to HIV-positive people suffering hardship, announced it was merging with THT.
Crusaid, which is in £22,000 of debt, spent only 39 per cent of its income on charitable activities in the last year.
NAT and THT also spoke of their concern that a “vital” £25 million HIV/AIDS support grant was no longer being ringfenced.
Communities secretary Eric Pickles announced the change last week, which means local authorities will no longer have to set aside the money to pay for specifc services for people with HIV.