The NSW Waratahs have ground out an essential bonus-point victory and denied Moana Pasifika an emotional triumph.

The hosts prevailed 29-14 on Friday in Sydney, but only after trailing 14-12 at halftime and being forced off with just 11 minutes remaining for 40 minutes due to nearby lightning strikes.

The weather forced the Duke and Duchess of Sussex Harry and Meghan, in the company of rugby royalty including John Eales, out of their seats in the second half.

Pasifika, whose ownership on Wednesday confirmed it would be unviable to continue funding the outfit beyond this year, started well and had their chances to build a lead early in the second half.

But twice they knocked on close to the line and then piggy-backed the hosts towards their own line with scrum ill-discipline and line-out errors.

Eventually, after some sloppy unforced errors of their own, the Waratahs pounced.

Isaac Kailea crossed after repeated, pounding efforts from close range, then  Sid Harvey had his second to make it 22-14.

The fullback didn't get a chance to convert his own try, players forced off due to the electrical storm and forced into the changerooms.

He hooked it past the upright on resumption but made a huge play to knock a ball loose just as Pasifika's Solomon Alaimalo had broken clear.

Semisi Tupou Ta'eiloa's own hand then denied him a try near the posts, the flanker held up in goal with five minutes to play.

The Waratahs controlled possession for the final minutes and Folau Fainga'a's rolling-maul try secured the extra point on the buzzer.

Earlier, Pasifika halfback Melani Matavao caused all sorts of problems in the first half with two tries from quick taps around the ruck.

The crafty No.9 played it perfectly, knocking on deliberately after earning the penalty before running through an offside Waratahs defence.

Tristan Reilly and Harvey, athletically diving into the corner, both scored to keep the hosts close at the break.

Victory broke a three-game losing streak to Pasifika and improved the Waratahs to 4-4 and in sight of the top six.

Moana (1-8) had lost their past seven games, conceding an average of 48.3 points in those losses, but arrived in Sydney with plenty to prove.

NSW Waratahs 29 (Tries: Reilly, Harvey 2, Kailea, Fainga'a; Cons: Harvey 2) def Moana Pasifika 14 (Tries: Matavao 2; Cons: Pellegrini 2)

Teams:

Waratahs: 15 Sid Harvey, 14 Andrew Kellaway, 13 Joey Walton, 12 Lawson Creighton, 11 Max Jorgensen, 10 Jack Debreczeni, 9 Jake Gordon, 8 Pete Samu, 7 Charlie Gamble, 6 Angus Scott-Young, 5 Miles Amatosero, 4 Matt Philip (captain), 3 Daniel Botha, 2 Ethan Dobbins, 1 Tom Lambert.
Replacements: 16 Folau Fainga’a, 17 Isaac Kailea, 18 Siosifa Amone, 19 Angus Blyth, 20 Clem Halaholo, 21 Jamie Adamson, 22 Teddy Wilson, 23 Triston Reilly

Moana Pasifika: 15 William Havili, 14 Tuna Tuitama, 13 Solomon Alaimalo, 12 Tevita Latu, 11 Glen Vaihu, 10 Patrick Pellegrini, 9 Melani Matavao, 8 Semisi Tupou Ta’eiloa, 7 Semisi Paea, 6 Miracle Faiilagi (captain), 5 Veikoso Poloniati, 4 Tom Savage, 3 Chris Apoua, 2 Millenium Sanerivi, 1 Abraham Pole
Replacements: 16 Samiuela Moli, 17 Malakai Hala-Ngatai, 18 Paula Latu, 19 Jimmy Tupou, 20 Ola Tauelangi, 21 Jonathan Taumateine, 22 Faletoi Peni, 23 Tyler Pulini

Referee: Angus Mabey
Assistant Referees: Mike Winter, Ben Woolerton
TMO: Aaron Paterson