The U-turn follows a recent controversy involving Chinese artist Ai Weiwei.
In October last year, Ai accused Lego of censorship when it refused to sell its bricks directly to him.
The company said its policy was to reject requests if it believed the bricks would be used to make a political statement.
Ai wanted to make an artwork on political dissidents.
The artist ended up using bricks donated to him by the public for an exhibition in Melbourne, Australia.
In a statement posted on its website on Tuesday, Lego said it used to ask customers ordering bulk purchases for the "thematic purpose" of their project, as it did not want to "actively support or endorse specific agendas".
"However, those guidelines could result in misunderstandings or be perceived as inconsistent, and the Lego Group has therefore adjusted the guidelines for sales of Lego bricks in very large quantities," it said. Read more on bbc.