The track leads the tally for a third week, trailed by Carly Rae Jepsen's 'Call Me Maybe' at two and Maroon 5's 'Payphone' at three.
Elsewhere, Pitbull leaps from 11 to six with 'Back in Time' and Karise Eden lands at nine with 'Nothing's Real But Love'.
Further down the chart, Usher vaults 18 to 11 with 'Scream', Justin Bieber bounds 20 to 14 with 'Boyfriend', and Rachael Leahcar debuts at 15 with 'Hands'.
Bieber's 'Turn To You' lands at 25, Viktoria Bolonina starts at 28 with 'Bang Bang', and Gym Class Heroes and Ryan Tedder are at 38 with 'The Fighter'.
The Top 10 singles in full (click where possible for our reviews):
1. (1) Flo Rida: 'Whistle'
2. (2) Carly Rae Jepsen: 'Call Me Maybe'
3. (3) Maroon 5 ft. Wiz Khalifa: 'Payphone'
4. (5) Nicki Minaj: 'Starships'
5. (4) Ed Sheeran: 'Lego House'
6. (11) Pitbull: 'Back In Time'
7. (6) Rihanna: 'Where Have You Been'
8. (7) Florence + the Machine: 'Never Let Me Go'
9. (*) Karise Eden: 'Nothing's Real But Love'
10. (8) Delta Goodrem: 'Sitting On Top Of The World'
Listen to Flo Rida's 'Whistle' below: