Ms Flood's tenure leading the Community and Public Sector Union will continue until 2020, while Michael Tull will continue as assistant national secretary and Alistair Waters will remain national president.

While Ms Flood was on leave and unable to comment, CPSU acting national secretary Michael Tull said her re-election, and the return of the executive team unopposed, was a vote of confidence in the union's leadership.

"Nadine has led this union through some challenging times in recent years, particularly the Abbott and Turnbull government's massive job cuts, and their harsh anti-worker and anti-union approach to enterprise bargaining for Commonwealth agencies," he said.

"Her resolve and experience has secured us important wins in the workplace while also leading successful community and political campaigns to oppose privatisations in Medicare, Australian Hearing and the ASIC registry."

Mr Tull said the union would focus on the ongoing arbitration case for Immigration and Australian Border Force workers in the Fair Work Commission, and the union-wide push to reform Australia's industrial relations system.

It also wanted to reverse the government's increasing use of consultants, contractors and labour hire, he said.

"Australia needs a strong public service that is properly resourced to meet the needs of the community it serves, and offers rewarding careers for those dedicated to serving the public interest," Mr Tull said.

Rupert Evans and Lisa Newman were re-elected deputy national presidents, while Beth Vincent-Pietsch and Melissa Donnelly were re-elected deputy secretaries.