West Australian Nationals Leader Terry Redman has yet to confirm whether his party will support legislation to enable the proposed sale of the Fremantle Port.

While the Treasurer Mike Nahan was confident of a sale later this year, it still had a number of hurdles to pass in Cabinet, including a final decision on approval to sell.

Dr Nahan believed Fremantle Port would sell for a minimum of $2 billion, but with the Nationals still refusing to commit to support a sale, some Nationals and Liberal MPs privately believed it would not go ahead in this term of government.

Dr Nahan confirmed senior Nationals and Liberal ministers met last week to discuss the sale, but the ABC was told that some within government believe the discussions did not go as smoothly as hoped.

While Mr Redman refused to comment on the meeting, Dr Nahan made it clear the Nationals, who are in an alliance in government with the Liberals, had raised some issues, including with the rail freight contract.

He recently said he was confident of a sale by July or August, but now appeared that timeline had been pushed back to later in the year.

"Depending upon passage through Parliament, I'm not totally in control of that," he said.

"I think we have all the numbers on there but, we think about October, September, November we will effect a sale.

"Generally there's a lag between final bids and final decision."

Asked whether the Nationals would support the sale legislation, Mr Redman still would not commit.

"We've got to take those things as they come," he said.

"It hasn't been through Cabinet yet and once it goes through Cabinet we will make our position known."

The Nationals indicated they would not support the sale unless certain conditions were met, including that grain and live export trade continued at a "fair and reasonable price".

Dr Nahan said he was confident of winning over the Nationals to support the sale.

"We will have debates with them and when they see the access and pricing regime, they will be comfortable," he said.

The ABC understands it was not only Nationals who were concerned about the sale, with even some of the Dr Nahan's Liberal Cabinet colleagues worried about the tight timeframe he had set, and they believed too many complex detail were yet to be finalised.