Outgoing UN rights chief Michelle Bachelet blasted Israel on Tuesday for failing to issue or renew visas for her staff to monitor the human rights situation in the Palestinian territories.

The United Nations high commissioner for human rights said it raised questions as to what Israel was "trying to hide" and vowed that her office would continue to report on the situation in the Gaza Strip and the occupied West Bank.

"In 2020, the 15 international staff of my office in Palestine -- which has been operating in the country for 26 years -- had no choice but to leave," Bachelet said in a statement.

"Subsequent requests for visas and visa renewals have gone unanswered for two years. During this time, I have tried to find a solution to this situation, but Israel continues to refuse to engage."

She said that as a member state, Israel had to cooperate with the UN in good faith and allow its officials to carry out their duties.

"Israel's failure to process visa applications that are necessary for my staff's access is inconsistent with these standards," Bachelet said.

The former Chilean president -- who leaves office on Wednesday after four years as the UN rights chief -- said Israel's treatment of her staff was part of a "wider and worrying trend to block human rights access" to the Palestinian territories.

"This raises the question of what exactly the Israeli authorities are trying to hide," she said.

Her statement said that in 2021, Israeli forces killed 320 Palestinians -- "a 10-fold increase on the number killed in 2020" -- and injured 17,042 people, six times the 2020 figure.

The UN recorded the highest number of incidents of settler violence since recording began in 2017, and arrests of Palestinians doubled last year.

"So far in 2022, Israeli forces have killed at least 111 more Palestinians," said the statement.

Despite the visa situation for international staff, Bachelet's office said it was still monitoring compliance with human rights obligations and providing technical assistance.

"We publicly report on violations by Israel, but also on violations by the State of Palestine, by Hamas in Gaza and Palestinian armed groups," said Bachelet.

"We will continue to deliver on our mandate. And we will continue to demand access to the occupied Palestinian territory for our staff, in line with Israel's obligations as a UN member state."

Bachelet's successor has yet to be appointed by UN Secretary General Antonio Guterres.