A ballot for industrial action by members of the CFMEU at NSW utility Essential Water has been approved.

The CFMEU is just one of three unions planning action against the state-owned company, as negotiations for new redundancy arrangements go quiet.

Both the United Services Union and the Town Employees Union are applying to hold a vote on industrial action too, while staff who are members of the Australian Manufacturing Workers' Union have already begun taking action.

The unions have been locked in a dispute with Essential Water over redundancy provisions several years now.

CFMEU spokesperson Greg Braes says all union activites have been above-board so far.

“We filed for protected industrial action with [the Fair Work Commission]. They approved for us to have a ballot, so now that's going ahead.

“That'll be run by the Australian Electoral Commission, it'll be a postal vote.”

Mr Braes said the vote would cover a wide range of possible action.

“There's a series of work bans, there's a series of stoppages, from hourly stoppages up to indefinite,” Mr Braes said.

“We've got from one hour up to 72 hours.”

The ballot should happen within a few weeks.