Australian Prime Minister Malcolm Turnbull, whose leadership has been questioned after a series of political setbacks, secured a much-needed legislative victory Tuesday with the passage of one of the two bills he used to trigger an election this year.

Australia's Senate, which the government does not control, passed a labor bill in an early morning sitting that will see greater oversight of trade unions and employer organizations.

Turnbull has seen his poll numbers slide to their lowest levels since he assumed the leadership in September 2015, and his future as prime minister has been questioned by political commentators as public confidence in the country's fourth leader in the last six years erodes.