Mr Tsang was forced to resign along with Finance Minister Joe Tripodi and Primary Industries Minister Ian Macdonald on a day in which Mr Rees "got rid of his liabilities", Greens MP John Kaye said.

"Henry Tsang was clearly an embarrassment to the NSW Government and was clearly under pressure, having been sprung for his relationship with Hightrade and forced to amend his parliamentary disclosure record four times in a fortnight.

"He had to go."

Mr Rees's office refused to give details about Mr Tsang's departure, which came just three days after the Premier told parliament Mr Tsang had given him assurances his "updates" of his annual returns disclosing the gifts and benefits he had received from Hightrade was complete.

At the State Labor conference at the Sydney Entertainment Centre over the weekend, the dumping of the three men was common knowledge by yesterday morning.

A few hours later Mr Rees's office issued a brief statement saying the three men had resigned.

Mr Macdonald issued a brief statement saying it had been an honour to serve as a minister.

Mr Tripodi spent 20 minutes taking questions from the media outside Parliament House in the afternoon, and defended the Premier's right to make the changes.

Mr Tsang did not issue a statement and did not respond to phone calls.

NSW Opposition Leader Barry O'Farrell said Mr Tsang's removal on the day that two other electorally unpopular ministers were removed showed Mr Rees lacked courage as a leader.

"Henry Tsang should have been stood down and sacked when it became clear that his relationship with Hightrade had not been disclosed," he said.

"Given that Hightrade is accused of employing illegal workers and is being investigated by the tax office for tax fraud and alleged phoenixing, the Premier should have taken action long before this."

Hightrade critic Mick Martin, of the Lower Hunter, said it was "good it happened, but the Government should be held responsible for letting Henry Tsang's relationship with Hightrade go for as long as it did".