When the GWS Giants train on Tom Wills Oval this season, they will be running out from the WestConnex Centre.

This week's announcement that the Sydney Motorway Corporation, the publicly funded body responsible for the controversial $17 billion WestConnex motorway project, would sponsor an AFL team have drawn allegations the government is using public money for "cynical" political advertising.

The St Peters Interchange that will make up part of Westconnex, shown here in an artist's impression.

"By all means the government should support the work sporting clubs do in the community but be upfront about it," said NSW Opposition Leader Luke Foley. "This is nothing more than a sneaky attempt … to buy some brownie points for WestConnex."

The corporation, which is structured as a private entity but funded by taxpayers, is refusing to disclose how much money it is spending on the three-year deal that grants it naming rights to the western Sydney team's training centre.