British author J.K. Rowling, pictured here in London in April, is a close friend of British Prime Minister Gordon Brown and his wife. (Lefteris Pitarakis/Associated Press)

J.K. Rowling, author of the Harry Potter children's books series, has contributed $1.9 million to Britain's Labour party, saying she believed the ruling party would protect poor families.

"The Labour government has reversed the long-term trend in child poverty and is one of the leading EU … [governments] in combating child poverty," said the writer of the popular wizard-in-training books, whose fortune is estimated at more than $1 billion.

Rowling wrote the first of her seven Potter books while still an unemployed single mother in the early 1990s.

The 43-year-old writer, known to be a personal friend of Labour Prime Minister Gordon Brown and his wife, Sarah, was critical of David Cameron's opposition Conservative party, referring to the party's platform of tax breaks for married people.

"It sends the message that the Conservatives still believe a childless, dual-income but married couple is more deserving of a financial pat on the head than those struggling, as I once was, to keep their families afloat in difficult times," Rowling said.

Her donation was the first cash contribution she's made to Labour.

Rowling's financial endorsement could bring a much-needed boost to the beleaguered prime minister, who has been criticized from within his own ranks and been the focus of an insurrection by party members.

"I thank her for supporting the Labour party and our values of social justice and opportunity for all," said Brown in a statement released late Friday.

The Conservatives lead by some 20 points in opinion polls. Party officials had no comment about Rowling's donation.

Rowling's last book in the Harry Potter series, Harry Potter and the Deathly Hallows, was published in July 2007.

The series has sold an estimated 400 million copies and been translated into 60 languages.