New Zealand could be days away from losing its "highest-profile international sporting event" should the Government not approve plans for the ASB Classic tennis tournament in January.

According to ASB Classic tournament director Karl Budge, organisers have been in talks with the Government for three months but remain in the dark after submitting their "robust" Covid-19 isolation arrangements for the event.

"We're still waiting to hear back on our plan; we've been in conversation for the last three months. We are waiting for approval, really some feedback on what it is we need to adhere to," Budge told Newstalk ZB's Heather du Plessis-Allan.

With the leading tennis tours around the globe about to confirm their calendars for 2021, Classic organisers are running out of time, Budge said.

"It is days, not weeks. We are certainly at SOS stage. We are a matter of days away from missing our cut."

While Budge is confident of landing the likes of tennis superstars Serena Williams, Naomi Osaka and Bianca Andreescu for the 2021 event, he says he cannot lock them in without sign-off from the Government.

Budge's plea came only hours after New Zealand Cricket confirmed their summer schedule after receiving approval from the Government to host international matches — and shortly before Netball New Zealand announced a three-game home series against England starting next month.

America's Cup syndicates have also received approval to arrive ahead of the event set to start in February 2021, with American Magic team members recently completing their 14-day managed isolation and some members of Challenger of Record Luna Rossa halfway through theirs.

Budge told Du Plessis-Allan their plan is to have international players isolate for three days, take the necessary Covid-19 tests which — if they come back negative — will allow players to compete while remaining in their bubble.

"We've got a plan we think is pretty robust, that not only is commercially viable and highly appealing both domestically and internationally, but importantly, it's one we think we can keep everyone involved safe."

Budge said he was confident players would follow strict isolation rules in a similar way they had during the recent US Open.

"We need to give them [the players] certainty as well; I mean, this is their job," he said.

"If we don't get some signed-off plans in a hurry, we are at risk of losing what has become our highest-profile international sporting event.

"We've won best international event five of the past seven years on the WTA Tour. We know we can run a great show; we get the sold-out sign."

Meanwhile, Prime Minister Jacinda Ardern yesterday ended hopes of All Blacks receiving quarantine exemptions when returning to New Zealand from the Rugby Championship.

The tournament will take place in Australia over the course of six weeks, with the All Blacks' final game scheduled for December 12 — a decision that was taken by governing body Sanzaar without New Zealand Rugby's approval.

Based on current rules, players will need to self-isolate away from families until December 27 — with some expected to opt out of playing in the tournament.

Ardern, however, said the Government needed to be consistent.

"We are asking people to go into managed isolation, and many will be in there over the Christmas period," she said.

"The easiest way to solve the issue the All Blacks are facing is if we stick to the existing game dates that concluded on the sixth of December."

Sanzaar remain confident the tournament will go ahead despite NZR's outrage at the schedule.