Simmons is campaigning against New York drugs laws

The Lobbying Commission is looking into whether Simmons spent more than $2,000 (�1,200) to influence state officials.

Anyone spending above this amount to lobby the state government must register with the commission and make financial disclosures.

Simmons is founder of Def Jam Records and head of Rush Artist Management, which manages top-selling rap acts such as LL Cool J, Run-DMC and Public Enemy.

He is part of a coalition working to convince New York's state legislature to relax tough 1970s drugs laws.

The laws, enacted in 1973 by Republican Governor Nelson Rockefeller, carry sentences of 15 years to life for anyone convicted of selling or possessing small amounts of drugs such as cocaine or heroin.

Lobbying Commission Executive Director David Grandeau said: "The commission is investigating Russell Simmons and other folks to see if they engaged in lobbying without properly registering with the state and documenting their spending."

The commission is also investigating whether Simmons gave a gift of a free helicopter ride to Secretary of State Randy Daniels last week, Mr Grandeau said.

State officials are not allowed to accept gifts worth more than $75 (�45).