Berry, who featured in one Test for the women's side, and Robertson, a former under-20 and rugby sevens player, were each given four-year suspensions.

Club players Ben Qauqau-Dodds and Rhys Pedersen have been banned for two years and 21-months respectively.

Charges were brought against the four athletes by Drugs Free Sport New Zealand (DFSNZ) amid an ongoing probe into the purchase of banned drugs on website Clenbuterol NZ.

The owner of the website, Josh Townshend, was jailed for two years for advertising, possessing and supplying banned substances.

Townshend collected a database which contains the names of over 100 sportsmen and women who used the service between 2014 and 2015, which is being investigated by DFSNZ.

All four players accepted at least one of the charges against them.

They were accused of possession and, in some cases, use or attempted use of clenbuterol, while Qauqau-Dodds has been banned for the possession and use or attempted use of Metandienone.

"What this investigation has revealed is that there is a lot of ignorance in our community game on the issue of performance-enhancing drugs," New Zealand Rugby general manager Neil Sorensen said, according to Agence France-Presse.

"What has happened to these four rugby players serves as a reminder that all athletes have to be very careful about what they put into their bodies."

It was initially thought that there were not any elite-level players on the list and that it was mainly comprised of amateur sportspeople.

Ice hockey players Mitchell and Lachlan Frear were the first athletes implicated to be banned in December.

The brothers were both suspended for two years.

Cricketer Chris Ware was also sanctioned as part of the probe.

He was banned for two years, backdated to January 1, 2017.