The plans were revealed in a document sent out by the government for consultation on Thursday.
The proposed crackdown on sick benefits is intended to take effect on 1st July next year.
The government had previously announced that people who have been on sick leave for three months would be assessed to see whether they could work for their existing employer in a different position. After six months, their capabilities will be assessed against other available jobs.
People who cannot work after six months' sick leave, who are waiting for an operation or who are a ‘special case' will be able to continue to claim sick benefits for a maximum of 30 months.
Unions on Thursday expressed dismay at the stricter rules.
“It's altogether too inflexible and many people will be adversely affected,” said Stefan Löfven, chairman of industrial workers' union IF Metall.
Löfven said he wanted cooperation between those involved to make the state sickness insurance system work. He said the new system risked focusing too much on various time limits.
“Many people are going to find that they are suddenly shut out of the insurance system,” Löfven said. He also expressed irritation that the government had not taken into account the fact that unions and employers' organizations were currently carrying out a joint review of sick benefits.
“We are sitting down and negotiating right now, and the government knows this. But we are not included in their thinking,” he said.