Labor will attempt to compel employers to take reasonable steps to prevent sexual harassment behaviour.
The Morrison government has legislation before parliament which responds to most of 55 recommendations from the landmark Respect at Work report.
But the opposition on Tuesday outlined a range of proposed amendments aimed at going further than the coalition's reforms.
Labor wants the Fair Work Act to prohibit sexual harassment and introduce a positive duty on employers to prevent it happening in the first place.
Complainants would receive cost protections to avoid people being discouraged from taking legal action against perpetrators.
Unions and other organisations would be allowed to launch legal action on behalf of complainants.
If the amendments are successful, Labor has pledged to insist on them being retained setting up a potential parliamentary stalemate over the bill.
The government's bill bans harassment in the Sexual Discrimination Act.
Coalition legislation also allows the Fair Work Commission to issue stop harassment orders similar to bullying complaints.
Major employer groups have resisted the report's "positive duty" recommendation over fears it could expose businesses to multiple penalties.
Sex Discrimination Commissioner Kate Jenkins, who authored the report, has urged the government to include the measure.
