It's dress up day at Bay Oval today on Day Two of the first test in the Tegel Test Series against South Africa. Spectators are invited to come along in their best outfits and be in to win prizes throughout the day.

After lighting up the World Cup in India, Rachin Ravindra has shown he is just as prolific in the test arena.

The young superstar scored his maiden test century in Mount Maunganui as the Black Caps dominated South Africa on day one of the first test.

The tourists enjoyed a bight start at Bay Oval with two wickets in the first session, but that was as good as it got, with Ravindra (118no) and Kane Williamson (112no) grinding South Africa down with a mammoth unbeaten stand.

With the score 39/2 when Ravindra joined his skipper at the crease, the pair plundered the Proteas for 219-runs to finish at 256/2 at stumps.

Back from a hamstring injury, Williamson shook off some early cobwebs and settled in to a typically masterful innings, notching his 30th test century in style with a thunderous pull through midwicket.

Combining with his captain, Ravindra showed great temperament and courage, hitting South Africa's most experienced bowler back over his head for six when pressure was mounting.

Much has been made about the inexperienced Proteas squad, but the players came out firing and struck early.

Tshepo Moreki, one of six debutants for the Proteas, had Devon Conway trapped in front with his first delivery in test cricket.

Following Conway's dismissal for one, fellow opener Tom Latham carved off a couple of quality boundaries but he didn't last long either, knicking one behind off the bowling of Dane Paterson.

However, it would be the last success for South Africa.

Williamson took some time to settle, surviving an absolute peach first up from Moreki but he eventually found his timing and he and Ravindra took his side to lunch with the loss of two wickets.

The pair brought up the 100 for New Zealand in the 44th over, as each registered half centuries shortly after, Ravindra with a cracking on drive.

They would both enjoy reprieves as South Africa dropped catching chances from the centurions.

Williamson's 30th hundred of his career came from 241 balls while Ravindra's three figures came from 190 deliveries.

The 200-run partnership came up shortly after tea, as the pair piled on the runs in the late stages.

Ruan de Swardt was the pick of the Proteas bowlers who all toiled hard for little reward.

The Tegel Test Series against South Africa continues today at Bay Oval, Mount Maunganui from 11am. Follow play LIVE In NZ on DUKE, TVNZ+, SENZ Radio and The ACC.

Jonty Dine/RNZ