Turnbull government MP Steve Irons has spent nearly $17,000 on unexplained "electorate business" 3500 kilometres from his home, including charging taxpayers to travel to Melbourne's Spring Racing Carnival just days after billing the public for flights to his own wedding.

The Coalition backbencher has already repaid more than $10,000 in travel claims after conducting a "self-audit" in 2013, including for flights for Mr Irons and his wife Cheryle​ to attend sporting events, as well as their 2011 wedding.

A Fairfax Media analysis of travel declarations by Mr Irons shows the MP has claimed at least five inter-state trips as electorate business, despite the destination being nowhere near his Perth-based seat of Swan. These include: