Jakarta – Indonesia's justice minister lashed out on Tuesday at a UN investigator examining the country's judiciary for branding the legal system as among the worst he had seen.

United Nations special rapporteur Param Cumaraswamy said over the weekend that President Megawati Sukarnoputri's government lacked the political will to root out graft and implement legal reforms critical to luring investors back to Indonesia.

Minister Yusril Ihza Mahendra said Cumaraswamy had exceeded his authority during a fact-finding mission to Indonesia, where the legal system has been criticised over issues ranging from lack of transparency to unpredictability.

"I questioned his statements on how bad the legal system is in Indonesia. I said to him, 'I've met several UN rapporteurs before but none has launched a political attack, especially on the president'," Mahendra told reporters.

"I asked what was his mandate, and he said collecting data. So, I asked 'why did you utter those comments and judge the government'. He denied having done that." Mahendra was speaking after a three-hour meeting with former commercial lawyer Cumaraswamy, a Malaysian.

Cumaraswamy, who among other things is looking into judicial graft in Indonesia and the independence of the judiciary, said he had a good debate with Mahendra.

"All I can say is that we had an open discussion on the concerns which I've already expressed ... the minister expressed his views on this matter and there are issues which we agreed and some issues where there was no agreement," he said.

Cumaraswamy arrived a week ago on a 10-day mission. He will report his findings to the UN Human Rights Commissioner next April. Cumaraswamy said he would announce his preliminary observations to the media on Wednesday.

On Saturday, he said: "I didn't realise the situation would be as bad as I have seen, particularly the structure of the system." Indonesia's legal system was dealt a fresh blow last month by a controversial bankruptcy ruling against a local unit of Canadian insurer Manulife Financial Corp.

Manulife alleged bribery influenced the ruling by the Jakarta Commercial Court on June 13. Mahendra's office is probing the allegations and is expected to announce the results this month.

The minister said he rejected some ideas from Cumaraswamy, including firing graft-tainted judges. "He advised we investigate corrupt judges and fire them. If I find indications of graft, I'll send the case to court," he said.

Mahendra added that Indonesia should not pay too much attention to foreign advice on how to reform its government.