Sinodinos inquiry not a stunt: Wong

Labor denies it's engaging in a stunt by forcing cabinet minister Arthur Sinodinos to front a Senate inquiry into political donations.

"Not at all, this is a man who is a cabinet minister," Labor's Senate leader Penny Wong told ABC radio on Wednesday.

Senator Sinodinos was treasurer of the NSW Liberal Party when it accepted about $700,000 in secret donations ahead of the 2011 state election.

The NSW Electoral Commission is refusing to pay the party more than $4.4 million until it reveals the secret donors.

Labor won Senate backing for the inquiry into entities associated with political parties, including a provision that Senator Sinodinos be directed to appear.

Attorney-General George Brandis said that would set a "shocking" precedent.

But Labor argues standing orders allow senators to be directed to appear before upper house committees.