Beyonce lip-synced her performance of the national anthem at US President Barack Obama's second inauguration, reports say.

The pop superstar was lauded for delivering a pitch perfect performance at the inauguration, despite struggling with sound issues.

However, the London Times today revealed she was not singing live.

Kristen DuBois, a spokeswoman for the Marine Corp Band which backed the anthem, told the paper Beyonce decided just before her performance to rely on a pre-recorded backing track.

"We did pre-record it and it was Beyoncé's decision at the last minute to go with the pre-recorded version," she said.

It was standard procedure to record backing tracks for inauguration performances, where cold weather is often a factor, she said.

"We pre-recorded all music as a matter of course and have done since time immemorial," she said. "This is our 54th inauguration... There is no question of there not being any music - it's not because the performer cannot do it."

A representative for Beyonce did not immediately respond to requests for comment.

Kelly Clarkson's representative said she sang live to perform My Country, 'Tis of Thee.

The use of a recording is typical in big events. In 2009, cellist Yo-Yo Ma was questioned about "hand-synching" for Obama's first inauguration. Ma said instruments weren't functioning properly in 19-degree weather.

It wasn't the only controversial performance of the day.

Rapper Lupe Fiasco was removed from the stage at an inauguration party concert after singing a song that included anti-Obama lyrics.

Organisers insisted he was only asked to leave the stage because his performance "wasn't up to scratch".

- Herald Online and AP