Alun Wyn Jones will start for the Lions, with Rhys Webb on the bench, when they take on New Zealand in the first test on Saturday.
Ireland flanker O’Mahony, who led theLions in the victory over the Maori All Blacks, will skipper the side at Eden Park.
Lions Head Coach Warren Gatland said: “We have picked a side based on form with a lot of players putting their hands up, especially from the Crusaders and Maori All Blacks games, and it was a lively selection meeting.
“The win against the Chiefs was also extremely important for the squad and some players played themselves into the side.
“We have continuously been strong at set piece and have been good defensively in the last two or three outings. But to beat the All Blacks you have to be courageous and play some rugby – you have to score tries and I think we have picked a team capable of doing that.”
The pack is retained from the Crusaders victory, including the back row of O’Mahony, Sean O’Brien and Taulupe Faletau and Gatland added: “It’s a reward for how the back row has gone. There is a nice balance there while Peter captained the side against the Maori All Blacks and has done a good job.”
There are seven Test Lions in the starting XV with three more on the bench in a match day squad combining experience and form.
Liam Williams is selected at full back and Elliot Daly on the wing following the four-try victory against the Chiefs on Tuesday and Gatland added: “Elliot has been very accurate in the way he has played and we saw some excellent attacking play from Liam on Tuesday night. We are excited about the 15 that take the field but also the very strong and experienced bench players who will have an impact.”
British & Irish Lions (v New Zealand, 1st Test, Saturday, June 24, 7.35pm NZST, 8.35am BST)
15. Liam Williams – Scarlets, Wales, #833
14. Anthony Watson – Bath Rugby, England, #816
13. Jonathan Davies – Scarlets, Wales, #778
12. Ben Te’o – Worcester Warriors, England, #815
11. Elliot Daly – Wasps, England, #822
10. Owen Farrell – Saracens, England, #780
9. Conor Murray – Munster, Ireland, #790
1. Mako Vunipola – Saracens, England, #787
2. Jamie George – Saracens, England, #819
3. Tadhg Furlong – Leinster, Ireland, #818
4. Alun Wyn Jones – Ospreys, Wales, #761
5. George Kruis – Saracens, England, #817
6. Peter O’Mahony (capt) – Munster, Ireland, #832
7. Sean O’Brien – Leinster, Ireland, #796
8. Taulupe Faletau – Bath Rugby, Wales, #779
16. Ken Owens – Scarlets, Wales, #829
17. Jack McGrath – Leinster, Ireland, #827
18. Kyle Sinckler – Harlequins, England, #814
19. Maro Itoje – Saracens, England, #825
20. Sam Warburton – Cardiff Blues, Wales, #800
21. Rhys Webb – Ospreys, Wales, #820
22. Johnny Sexton – Leinster, Ireland, #791
23. Leigh Halfpenny – Toulon, Wales, #775