In the four months since July there had been 46 boats discovered fishing illegally, including five destroyed at sea, as compared to 337 boats in 2021 to 2022.

85 illegal fishing boats were discovered in 2020 when the pandemic was declared.

Chief Executive of the Australian Fisheries Management Authority Wez Norris told the hearing that the vast number of the boats were from Indonesia.

"COVID has resulted in greater push factors from the Indonesian side, things like the wholesale closure of tourist venues, and people moving back into into regional villages and ports," Mr Norris told senate estimates.

He said a damaging cyclone in Indonesia in 2021 also had implications for livelihood and food security, while Australia's ability to board illegal vessels was also reduced during COVID.

Minister for Agriculture and Fisheries Murray Watt told the estimates committee hearing on Tuesday that some people in other countries had sought alternative income when COVID began.

"There's some evidence to suggest that countries that had been reliant on tourism income, with tourists drying up people decided to explore other ways to make a living," Minister Watt told the senate estimates hearing.

The minister said he had been due to talk to his Indonesian counterpart about illegal fishing when he visited the country earlier this year but the meeting was deferred by the Indonesians.

Mr Watt said managing illegal fishing is a shared concern between the two countries.

"Some of their waters are exposed to illegal fishing from other countries as well, so I wouldn't want people to get the impression that it's all about us going in and scolding them about doing the wrong thing," Senator Watt said.

Australian Associated Press