The Ministry of Marine Resources is monitoring the operation, 1300km north-east of Rarotonga, alongside the Pukapuka Island Government.
The ministry says a compliance team of two fisheries officers, a biosecurity officer and an immigration officer are overseeing the operation.
And afterwards, the Compliance Team is expected to return to Rarotonga on board the carrier vessel.
A police officer in Pukapuka is also assisting the team for Customs purposes.
The ministry says Pukapuka has been a transhipment port for several years as it is nearer the fishing grounds in and around the northern Cook Islands exclusive economic zone. Licensed longline vessels are authorised to fish within the zone outside 50 nautical miles from each island.
The last in-port transhipment in the Cook Islands longline fishery was carried out in Rarotonga in June.
During the transhipment both the carrier vessel and longline vessels are fully inspected for compliance, authorisations and documentation.
The compliance team will also use catch log sheets and other documents to ensure all fish product is legally caught and documented.
This information is also correlated against other data sources such as observer and unloading, and the satellite-based vessel monitoring system.
The ministry says they have developed a rigorous monitoring, control and surveillance system to ensure that the amount of fish caught can be compared to set quota limits.