Ontario's social services minister says she won't attend a protest planned at the legislature on Thursday by parents of children with autism because she has received threats.

Lisa MacLeod did not detail the nature of those threats or say if she has alerted the police to them.

But she says she won't be going out to the protest on the lawn of the legislature because the tone of the debate has given her concerns about her personal safety.

Families of children with autism are set to protest a new program unveiled last month by MacLeod that they say will leave kids without access to the level of treatment they need.

The Financial Accountability Office also says today that they will investigate the budget for the autism program, after the Liberals raised concerns about the government's claims.

MacLeod has said the Progressive Conservative government increased the autism program budget to $321 million from $256 million, but the Liberals, who were previously in power, say their government had also budgeted the larger amount.