Australia have added leg-spinner Mitchell Swepson to their squad for the third and final Test of the ongoing three-match series against New Zealand.

The 26-year-old has played one T20I for Australia, against England last year, and was part of the Test squad for the tours of India and Bangladesh in 2017, but is uncapped in the the longest format.

Cricket Australia national selector Trevor Hohns said Swepson has been rewarded for some excellent showing this summer, where he recorded 12 wickets from six Sheffield Shield games at 26.58. 

"Having Mitch in Sydney gives us the option to play two specialist spinners if the conditions demand. We will make those assessments when we get to Sydney," Hohns said. 

In a statement, Cricket Australia said that Swepson would join the squad during the ongoing Boxing Day Test in Melbourne.

Meanwhile, right-arm pacer Peter Siddle will return to play in the ongoing ninth edition of the Big Bash League, having been left out of the XI as Australia went with James Pattinson at the MCG.

"Having Sids (Siddle) as the 13th man and his experience at the MCG has been invaluable," Hohns said. "His insights have greatly assisted the fast bowlers for this Test and it was great having him around the group." 

Australia currently leads the three-match series 1-0, having won the first Test by 296 runs in Perth.