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Tests were scheduled in Samoa and Tonga in June, but they have confirmed games could yet be moved to New Zealand.
The Welsh Rugby Union (WRU) say it wants to play on the islands, but will pursue alternatives if guarantees over player welfare are not met.
"There is no issue with Samoa as a venue," World Rugby told BBC Wales.
Wales are scheduled to play against Samoa on 24 June 2017 at Apia Park, Apia.
The sport's governing body helps tier two countries meet costs of hosting tier one nations.
World Rugby helped with appropriate medical cover when New Zealand played Samoa in Apia in 2015.
A delegation from World Rugby is scheduled to travel to Tonga and Samoa to assess whether facilities in each country are fit for purpose.
"Several other international sides have played in Samoa successfully in recent years," World Rugby explained.
"As regards Tonga, a new venue is due to be constructed there and we need to assess whether it will be completed in time for the fixture to take place as planned.
"In addition, from a due diligence point of view, we will be conducting a site visit in Tonga within the coming weeks to ensure that other facilities in Tonga are of the appropriate level to host a match of this nature.
"This would include accommodation, training facilities and medical provisions. As always, our number-one priority is player welfare.
"No decision has yet been taken on this. By way of contingency, it is possible the match could take place in Auckland if we cannot proceed with Tonga."
The original itinerary for Wales' tour was thought to include a third Test in Fiji, but BBC Wales understands this is no longer part of the schedule.
Fans and travel companies are currently in a state of limbo, with hundreds having registered for the tour.
Wales last toured the Pacific Islands in 1994.
The WRU say it expects a final decision to be made by the end of October.
A spokesman for the Samoan Rugby Union said: "At this stage we can't comment as the match has not yet been confirmed by World Rugby."
The Tongan Rugby Union has also been asked to comment, but has not yet responded.

David Lytton's body was discovered at Dove Stone Reservoir in Greater Manchester on 12 December 2015.
He was born David Lautenberg on 21 April 1948 but his name changes to Lytton on the electoral register in 1987.
The 67-year-old flew into London Heathrow from Lahore, Pakistan, two days before his body was found.
He was identified from photos from a passenger list and picked up on CCTV in London.
Greater Manchester Police (GMP) said his identity was confirmed as a result of a DNA match with a relative.
The electoral register examined by BBC Newsnight showed David Lautenberg was listed as living at 46 Lilian Road, London, SW16 5HN from 1982 to 1986, while David Lytton was listed there from 1987 onwards.
It is understood he changed his name due to a family feud, the Guardian reported.
Mr Lytton, who had lived in Pakistan for 10 years, was found fully clothed, lying prone on the ground above the reservoir.
He had no wallet, phone or other identification and remained unidentified despite numerous public appeals and the release of CCTV footage of his last known movements.
In June 2016, the BBC investigated the mystery of the unidentified body.
Why did this man travel 200 miles to die on Saddleworth Moor?
Police said a "provisional" cause of death had been determined as "strychnine poisoning". Police believe he took his own life.
An international police investigation was launched after a post-mortem examination revealed he had a type of titanium plate in his leg which was only manufactured and fitted in Pakistan.
Greater Manchester Police and the National Crime Agency contacted the medical community and the British Embassy in Pakistan to appeal for information.
DNA analysis confirmed that he was David Lytton from London, who had "no obvious connection" to Saddleworth.
Mystery still surrounds the case and why he chose to head to Greater Manchester after returning from Pakistan.
A full inquest is due to take place on 14 March.
World Rugby have moved to allay fears that Wales's 2017 South Pacific tour is in doubt because of concerns over facilities and medical cover.
[NEXT_CONCEPT]
A mystery man who was found dead on Saddleworth Moor had previously changed his name.