Google is to pay its gay and lesbian workers extra in order to compensate them for unequal tax laws.

Federal laws which do not recognise gay relationships mean that gay workers must pay an extra tax when their partners receive domestic health benefits.

Straight married couples do not have to pay this penalty, which has been estimated to be as high as $1,000 a year.

The pay raise will be retroactive to the beginning of 2010 and will apply only to employees in the US.

Straight staff who are not married will not benefit from the change, as Google says they are able to marry and enjoy the tax break if they wish.

Laszlo Bock, Google’s vice president for people operations (human resources) said the company looked at its policies after a gay employee pointed out the disparity.

“If you were to add it all up, it’s not like we are talking hundreds of thousands per employee,” he told the New York Times. “It will cost some money, but it was more about doing the right thing.”

Google is not the first large company to offer the benefit to gay employees.

However, it may encourage other Silicon Valley companies to follow suit.