The New South Wales Blues opening partnership of Nick Larkin and Daniel Hughes have amassed their second double century stand in the JLT Sheffield Shield this season against South Australia at the SCG on Saturday.

Larkin (109 not out) and Hughes (105 not out) both posted their centuries late on the second day. The opening partnership is 223 unbeaten at stumps, in reply, to 380 posted by South Australia.

The pair now hold the two highest partnerships for any wicket, and the only two past 200, in the Sheffield Shield this season to date.

The opening pair also shared a match-defining 251-run stand in the massive victory over Queensland at Manuka Oval in round four. The Blues won that match by 163 runs.

Larkin reached his century in 197 balls at the SCG on Saturday. He has struck four boundaries and two booming sixes, with the slog sweep, so far during the innings.

Hughes posted his fifth First Class century in the next over with a boundary. He reached the milestone in 236 deliveries. His determined knock has so far has included seven fours.

Earlier in the day, South Australia was dismissed for 380. It lost 5/61 in the morning session of what was a dominant day for the hosts.

Australian One-Day International wicketkeeper-batsman Alex Carey posted his second First Class century for South Australia and remained unbeaten on 110 from 183 balls.

South Australia resumed at 5/315 on the second day, but it was the Blues who made the perfect start.

The 134-run sixth wicket partnership between Tom Cooper and Carey came to an end in the second over of the day.

Sean Abbott (3-97) snared the crucial scalp of Cooper for 89 from 174 balls in his first over.

The Blues seamer was on a hat-trick when he claimed Nick Winter the very next ball, caught at leg gully, and the visitors were 7/319.

The wickets continued to fall for South Australia. Adam Zampa (7) was the next to depart to give debutant Greg West (3-88) his third wicket.

Abbott then dismissed Joe Mennie (4) with a brilliant delivery that nipped back off the seam, stayed low, and smashed into middle and leg stump.

Carey brought up his century in 156 deliveries and added a valuable 36 runs for the final wicket in partnership with Daniel Worrall.

Worrall was bowled by opening bowler Harry Conway (2-53) for 6. Nevill finished with four catches for the innings.

Larkin and Hughes then channelled their efforts against Queensland at Manuka Oval.

WATCH: NSW vs SA - Day 2 - Highlights

The pair survived seven overs before lunch and then added 81 runs in the second session to be 0/94 at tea.

They blunted the South Australian attack and continued to tick the scoreboard over in the final session.

The opening pair reached the hundred mark early in the last session and brought up their double century stand in the 68th over of 77 bowled by the visitors.

WATCH: Nick Larkin on scoring ton at the SCG

Full scorecard here: