By Fathin Ungku

SINGAPORE (Reuters) - Singapore should repeal its ban on foreign companies sponsoring the annual Pink Dot gay-pride event, Human Rights Watch said, complaining that it infringed freedom of expression in the city state.

Singapore announced this month that foreign firms would no longer be allowed to sponsor or participate in the rally, after this year's event drew record numbers of people and a record nine corporate sponsors, including Twitter, Google and Facebook.

The announcement came after this year's event on June 4.

"The ministry's June 7 statement sends a discriminatory message to Pink Dot’s corporate sponsors that their support for the festival is contrary to government policy," Human Rights Watch said in a letter to Home Minister K. Shanmugam.

"This infringes on rights to freedom of expression, which the Universal Declaration of Human Rights guarantees to 'everyone', and pressures corporations to act in contravention of their responsibilities under the United Nations Guiding Principles on Business and Human Rights."

The ministry said it had no immediate comment.

The event has been celebrated since 2009 under conservative Singapore's stringent public assembly laws at the "Speakers' Corner" near the city's downtown area.

Under Singapore law, sex between men is punishable by up to two years in jail, though prosecutions are rare.

Prime Minister Lee Hsien Loong said last year the country was not ready for same-sex marriage, while a "Wear White" movement started by religious groups to counter Pink Dot has entered its second year.

Singapore organizers of the musical "Les Miserables" last week cut a scene in which two male actors kiss after complaints from the public.

(Editing by Nick Macfie)