The parents of a Toowoomba man who had his testes removed after he died last month will oppose any attempt by their son's fiancé to use his sperm.

Tony Deane died unexpectedly in the Toowoomba Hospital, in southern Queensland, in April.

Documents show his fiancé Leith Patteson, successfully applied to the Supreme Court the next day to have his testes removed, so she could apply later to use his sperm to have a child.

The court was given several sworn affidavits from the couple's friends, who said they had already tried to conceive a child and were "ecstatic" when they thought they had fallen pregnant.

The pair met online in September 2015 and became engaged a month later after Mr Deane moved from New Zealand to Toowoomba.

Lawyer Bill Munro, who represents the man's parents, said Mr Deane's family was intending to oppose an application to use the sperm.

"On the information that is available at the moment their inclination is to oppose the making of any orders for the use of the sperm but a final decision won't be able to be made until they've been provided with all of the evidence," he said.

Mr Deane's parents, who live in New Zealand, were at their son's beside in Toowoomba when his life support was turned off.

They have since returned to New Zealand with their son's body.

Mr Munro said the situation had caused his clients great distress.

"The uncertainty associated with it has caused them significant distress and both the parents are receiving ongoing counselling in New Zealand in order to assist them to cope with this very stressful time of their lives," he said.

He said Ms Patteson's application took them by surprise.

"There was very little time for anyone to consider their position at all," he said.

"My client was only aware of the fact that the application was being made within a few hours prior to the courts actually being convened to hear the decision."

Mr Munro said he was only aware of two other similar cases in Queensland.

"It has certainly aroused great interest and of course the subjective aspect of it that it does impact on the life of an as yet unconceived human being," he said.

"Whether or not that conception ever proceeds is something the court will need to determine."

Lawyers representing Ms Patteson said it was inappropriate to comment further on their client's position at this time.