The states political parties have been warned by Ausgrid that they will be charged $50 per political placard that the company removes from its powerpoles in the lead-up to the state election on March 28.

In inner-city Sydney, political signs advertising the candidate, issue or party have been attached to power poles during election campaigns for almost as long as the poles have been in existence.

In the suburbs, parties have favoured front yards on prominent corners.

But this year, Ausgrid has taken umbrage at this co-option of its poles in the cause of democratic communication.

CEO Vince Graham has twice written to the political parties ahead of the poll, reminding them that the poles are Ausgrid's property.

But his latest letter has warned  a removal fee of $50 a corflute (sign) will be sent to parties if the posters are affixed.

In the past, Ausgrid has protested the use of its poles, but not taken action provided political parties removed their advertising at the end of the campaign.

ALP state secretary Jamie Clements said Labor was attempting to comply with Mr Graham's letter and had let the campaign offices know.

"He's always trying to stop it. He wants to stop people putting little holes in the poles he wants to sell to the Chinese," he said, referring to Ausgrid's support for the the Baird Government's plans to sell 99 year leases for 49 per cent of the state's poles and wires.

A spokesman for the NSW Liberals said the party would comply and had notified all candidates.

But the NSW Greens are fighting the move, saying Mr Graham is trying to stifle debate on the privatisation -- which the Greens oppose.

"The placement of election materials on NSW-owned electricity is perhaps as old as the first pole itself. To that end we are surprised that you now appear keen to change this long-standing tradition that enables smaller political parties in particular to compete with the massive electioneering budgets of the ALP and Coalition," the Green's campaign Manager, Chris Harris said.

The Greens have promised to remove all their signs at the end of the election, but say that because they do not direct their volunteers to put signs on the poles, the party cannot be held liable for $50 a poster Ausgrid plans to charge.

"The sudden increase in the threats or intimidation - however you choose to characterise it - seems to coincide with our opposition to privatisation of electricity assets," Mr Harris said.

He said the charges seemed to be aimed at small parties like the Greens who couldn't compete with large parties on advertising and relied on cheaper forms like posters.

In a statement Ausgrid said: "Attaching election posters to electricity poles creates a significant safety risk for both campaign staff and the community.

"There are strict safety rules and protections required for anyone working on or near electricity infrastructure, particularly adjacent to public roads. The unauthorised use of electricity assets is also a breach of both the Electricity Supply Act and the Graffiti Control Act, and fines may apply."