Porirua mayor's defending a trip to Western Sydney planned for November, calling the sister city relationship important. 

Anita Baker will travel to Blacktown for the inaugural Trans-Tasman Mayoral Cup, played between football teams from both cities. 

It'll cost ratepayers $2500 dollars in flights for Baker and a local kaumatua, with Blacktown's council providing accommodation.

Baker says she keeps costs low by not employing office staff - and managing rates rises. 

"We've had our sister city relationship with Blacktown for 42 years, so I think it's a reasonable expense." 

LISTEN ABOVE