Australia-bound Black Caps could be Test cricket's No.1

New Zealand will surge to the top of the world Test rankings if they topple Sri Lanka twice in their two-match series beginning on Wednesday, just four months before they head to Australia for a keenly-anticipated Trans-Tasman battle this summer.

The Black Caps, with 109 points, are currently ranked behind India on 113 points, but a 2-0 series win in Sri Lanka will see them leapfrog world cricket's heavyweights.

There is plenty of cricket to be played between now and the first of three Tests between Australia and New Zealand this summer, with India to face the West Indies, South Africa and Bangladesh later this year and the Black Caps to host two Tests against England before heading across the Tasman.

But the fact the Kiwis could take top spot in just a few weeks underlines their recent improvement in Test cricket, which has seen them lose just two of their past 18 matches.

Test rankings admittedly have less relevance with the new two-year ICC World Test Championship (WTC) now under way, culminating in a 2021 final at Lord's between the top two teams.

The WTC, which begun earlier this month with the first Ashes Test between Australia and England, has its own points table separate from the ICC's Test rankings.

It would nonetheless be a notable achievement for Kane Williamson's side to take the No.1 mantle, having never before ascended to the top of the standings, ahead of their tour of Australia which features three Tests including the marquee Boxing Day and New Year's matches.

"If that happens that would be great," captain Williamson told reporters in Galle on Tuesday. "But I guess there's a bigger picture.

"The thing with rankings is that they just fluctuate throughout a season. For us, we just want to be focusing on the cricket and give ourselves the best chance of success."

If New Zealand defeats Sri Lanka in both Tests, India would need to win both games of their two-Test series against West Indies in the Caribbean (which also begins this month) to hang on to top spot.

Williamson suggested the lure of securing a spot in the maiden WTC final was a bigger incentive for his side.

"I think it's a welcome addition to the Test format, bringing that context into every Test match you play," said the prolific batsman.

"No matter what team you play at any level it's very, very competitive.

"But now there's that added carrot where, in two years' time, everyone's vying for a spot in that championship final which would be a really exciting thing to be a part of."

Crisis-ridden Sri Lanka will be wary of providing a rank turning wicket in the first Test against the Kiwis in Galle after being outsmarted by England in the most recent encounter at the venue.

England overcame the battle with a variety of off-, leg- and left-arm spin as the trio of Moeen Ali, Adil Rashid and Jack Leach played a key role in a 3-0 series sweep.

The Kiwis too are carrying plenty of spin options and are likely to play two of them. Bombay-born left-arm spinner Ajaz Patel claimed five wickets in the warm-up game in Negombo and he is likely to be the second spinner to leggie Todd Astle.

Although seam is New Zealand's strength, they are likely to stick to two seamers with allrounder Colin de Grandhomme coming in as the third option.

Trent Boult will be the number one pick while they will have to make a call between Tim Southee and Neil Wagner, possibly the latter, who picked up nine wickets in New Zealand’s last Test match.

But the hosts will be no pushover, as they showed by winning their recent 2-0 series in South Africa - becoming the first Asian nation to do so.

"They are a strong team. They will come into this series with lot of confidence behind them after what happened in South Africa," said New Zealand coach Gary Stead.

But Sri Lanka have some tough choices, and in all departments.

The hosts have dumped head coach Chandika Hathurusingha halfway through his three-year tenure, with former fast bowler Rumesh Ratnayake now filling in on an interim basis.

When they trounced South Africa five months ago, rookie Oshada Fernando played a key role posting an unbeaten 75 in Port Elizabeth in what was his second Test match.

He became an instant hero and his subsequent snubbing from the World Cup squad earned the wrath of former players.

There will be more disappointment as Fernando, one of the brightest prospects to emerge in recent times, is set to miss both Tests with the return of Angelo Mathews, who was injured for South Africa.

"New Zealand will be tough to beat. We have got guys who were not part of the series in South Africa, so we have got to make some tough calls," said Sri Lanka skipper Dimuth Karunaratne.

Former captain Dinesh Chandimal, who also missed out on touring South Africa, is back in the squad and the wicketkeeper's slot will be a toss up between him and Niroshan Dickwella.

Lahiru Kumara, another player who didn't go to South Africa, will be Sri Lanka’s lead fast bowler and it remains to be seen with whom he will share the new ball.

Both Suranga Lakmal and Vishwa Fernando were main architects during the win in South Africa.

New Zealand squad: Kane Williamson (c), Jeet Raval, Ross Taylor, Colin de Grandhomme, Todd Astle, William Somerville, Mitchell Santner, Tom Blundell, Tom Latham, Henry Nicholls, B.J. Watling, Trent Boult, Tim Southee, Ajaz Patel, Neil Wagner

Sri Lanka squad: Dimuth Karunaratne (captain), Dinesh Chandimal, Lahiru Thirimanne, Oshada Fernando, Angelo Mathews, Dhananjaya de Silva, Kusal Mendis, Kusal Perera, Niroshan Dickwella, Akila Dananjaya, Lasith Embuldeniya, Lakshan Sandakan, Suranga Lakmal, Lahiru Kumara, Vishwa Fernando