Southee said the placings were reward for the quality of cricket New Zealand have been playing in the past year.
"Everyone does their part for the team, and those individual accolades take care of themselves," he said.
"You start worrying about them first, you slip away from what your main focus is. It's nice to be recognised but first and foremost it's about doing a job for the team."
Among the batsmen, McCullum and Williamson are in their highest-ranking spots, as are Sri Lanka's Angelo Mathews, Australian skipper Steve Smith and England's Joe Root.
Southee is also among the top 10 test allrounders, at No8, with Dan Vettori, despite playing only one test in the past two and a half years, at No10. Bangladesh's Shakib al Hasan leads that group, followed by South African Vernon Philander and Indian spinner Ravi Ashwin.
World top 10 rankings
Batsmen:
1 AB de Villiers (South Africa) 893 rating
2 Kumar Sangakkara (Sri Lanka) 891
3 Hashim Amla (SA) 887
4 Angelo Mathews (Sri Lanka) 877
5 Steve Smith (Australia) 853
6 Shiv Chanderpaul (West Indies) 848
7 Younis Khan (Pakistan) 818
8 David Warner (Australia) 815
9 Joe Root (England) 789
10 Misbah-ul-Haq (Pakistan) 777
Also:
11 Ross Taylor (NZ) 772
12 Brendon McCullum (NZ) 760
13 Kane Williamson (NZ) 753
Bowlers:
1 Dale Steyn (SA) 901
2 Ryan Harris (Australia) 851
3 Rangana Herath (Sri Lanka) 842
4 Vernon Philander (SA) 822
5 Mitchell Johnson (Australia) 812
6 James Anderson (England) 806
7 Trent Boult (NZ) 805
8 Stuart Broad (England) 774
9 Tim Southee (NZ) 767
10 Kemar Roach (West Indies) 766