Sports Minister and WestConnex Minister Stuart Ayres has been accused of a conflict of interest after accepting GWS Giants corporate hospitality at least 16 times before announcing a major taxpayer-funded sponsorship for the club.

Labor said Mr Ayres had failed to disclose at least three of the times he had attended GWS games in 2014 and 2015 as member for Penrith, then made his first act as WestConnex Minister the sponsorship of the club, for an undisclosed sum.

It is common for MPs to accept corporate hospitality at sports events, but it must be reported under pecuniary interest disclosure rules.

Opposition Leader Luke Foley said the problem was not only Mr Ayres' failure to disclose the three occasions, but the subsequent bestowal of a sponsorship to the same club under Mr Ayres' WestConnex portfolio.