Key Points:

The Government has found itself in the embarrassing position of jointly financing a $165,000 conference on drug policy with one of the world's leading advocates of decriminalising marijuana use.

Billionaire currency speculator George Soros' Open Society Institute has given $35,000 to this week's symposium, which will be attended by Government ministers, police and a judge and will examine New Zealand's drug laws.

Mr Soros is known for financing drug reform campaigns, and most recently backed a referendum in the American state of Massachusetts which decriminalised possession of small amounts of marijuana.

The Ministry of Health has put up $30,000 and the symposium organiser, the largely Government-funded NZ Drug Foundation, is paying $50,000.

The Society on Alcohol and Drug Dependence, a charitable trust, is putting up $50,000.

Health Minister Tony Ryall would not comment, but a spokeswoman said he did not know of the link to Mr Soros until the Herald's inquiry.

She said the Government's funding alongside that of Mr Soros' organisation was "definitely not" tacit approval for decriminalising marijuana.

The Ministry of Health confirmed its funding of the symposium last week. This was after Mr Ryall told the ministry to review its involvement with all conferences, and leaned on it to cancel a conference of more than 300 health professionals that would have cost $123,000.

The spokeswoman said Mr Ryall - who was listed on a draft agenda to open the symposium - found out about the ministry's sponsorship only late last week. She said it would now be opened by associate health minister Peter Dunne, who would be telling those attending "the Government absolutely does not support the decriminalisation of cannabis, and is committed to a strong enforcement of that law".

Labour leader Phil Goff said he would be concerned if there was "any motivation" by conference organisers to legalise marijuana, which the Labour Party opposed.

Drug Foundation director Ross Bell said the Open Society Institute was "at arms length" from Mr Soros, its founder and financial backer.

Its aim was to shape public policies that improved fairness in political, legal, and economic systems and safeguard fundamental rights.

It has previously funded projects that advocate decriminalising marijuana.

Mr Bell said the funding had no strings attached - there was no requirement to accept particular international speakers or ensure the agenda had "legalisers" on it.

Mr Bell said the institute's funding was a small amount of the cost of the two-day conference, and most attending would be paying a $850 entry fee.

Mr Bell said the foundation was "neutral" on the legal status of cannabis. It did not have a secret agenda, nor was it a liberal or pro-drug organisation as its opponents claimed.

The symposium's international speakers are led by Sandeep Chawla, one of the most senior United Nations drugs officials to have visited New Zealand.

New Zealand speakers will include Deputy Police Commissioner Rob Pope, Maori Affairs Minister Pita Sharples and principal youth court judge Andrew Becroft.

The symposium will address New Zealand's Misuse of Drugs Act, which was passed 34 years ago and is being reviewed by the Law Commission. It will also examine the United Nations' drug policy.

* George Soros

Currency speculator, philanthropist and political activist, ranked by Forbes as the 101st richest man in the world.

Known as a legaliser or a liberal because of his worldwide efforts to promote drug policy reform.

Most recently put US$400,000 towards a successful referendum in Massachusetts which decriminalised possession of less than one ounce (28g) of marijuana.

Once teamed with Peter Lewis, the American billionaire caught smuggling a small amount of marijuana into New Zealand in 2000, to finance an advertising campaign backing medicinal use of cannabis.