The grand secretary of the Orange Order has said a contentious bonfire in south Belfast should go ahead as planned, saying concerns about the presence of asbestos on the site are “clearly political”.

The Rev Mervyn Gibson was speaking ahead of the lighting of Eleventh Night bonfires across Northern Ireland on Friday, which usher in 12 July commemorations.

Concerns had been raised about asbestos at the Belfast site as well as separate fears over the power supply to two major hospitals because the bonfire is near an electricity substation.

Rev Gibson said if asbestos had been a major issue environmental agencies should have said so months ago, as bonfire builders had been on site since January.

The Northern Ireland Environment Agency has removed about 20kg of asbestos from the site, between the Donegall Road and the Westlink.

Mr Gibson told BBC’s Good Morning Ulster Programme that people should “go and enjoy themselves” at the bonfire.

“I think it’s clear for everybody that the decision that was made was a political decision. This asbestos has been there from 2017,” he said.

“I believe the council voted a couple of weeks ago for the bonfire to go ahead. A few days before it then Sinn Féin and Alliance and the SDLP decide to vote against it.”

On Thursday, police confirmed they would not assist in the removal of the bonfire. They had been asked by the council to assist contractors to dismantle the bonfire before it was lit.

The PSNI said that, after a multi-agency meeting, it was felt “the risk of the bonfire proceeding as planned was lower and more manageable than the intervention of contractors and the proposed methodology of dismantling it”.

Belfast City Council acknowledged the PSNI’s position but said it remained concerned about the presence of asbestos on the site and would continue to raise these concerns with the Northern Ireland Environment Agency (NIEA).

The council voted to write to the environment minister to act immediately to have the asbestos removed.

The NIEA said it was first alerted to the issues around the bonfire on 16 May, but “circumstances did not allow for the safe and controlled removal of the asbestos”, prior to the Eleventh, so the agency worked with the landowner and council to agree mitigating measures to reduce the risk to public health.

Mitigations included the further covering of the asbestos-containing material, the use of fire-retardant material and the erection of additional fencing.

The NIEA said it was their understanding that the landowner will arrange the removal of all of the asbestos from the site next week.

On Thursday, bonfire builders voluntarily removed tiers of pallets from the top of the bonfire and told BBC News NI the action was an “olive branch” to those concerned.

The police statement said that there had been an “evidence-based assessment” which had take all of the risks associated with the removal into consideration and they would continue to work with partners to “manage the remaining risks surrounding this bonfire”.

The Deputy First Minister and DUP MLA, Emma Little-Pengelly, has said: “No one wants anyone to be hurt or for there to be any risks to health or wellbeing”.

First Minister Michelle O’Neill has said it was “entirely wrong, and completely unacceptable for these bonfires to take place in a way that endangers property, infrastructure, public services or lives”.

Environment Minister Andrew Muir has urged the public to “exercise caution and common sense”.

Belfast Health Trust said the bonfire was near a substation that supplies Belfast City Hospital and the Royal Victoria Hospital.

Northern Ireland Electricity (NIE) said it had expressed concerns over the bonfire’s “proximity to the substation causing potential risk to critical infrastructure and power outages”.

The trust said it had contingency measures including back-up generators and it was confident there was no need to cancel any planned treatments or procedures.

The landowners, Boron Developments, bought the site in the summer of 2017 and were made aware of asbestos at that time.

Boron Developments have said it engaged a waste management company to remove the asbestos but the company needed “no personnel” on the site in order to complete the removal of asbestos.

Due to people “bringing in materials and building the bonfire” the company told the landowners it could not complete its work.

The council said while the lands at the site remained “the responsibility of the landowner” the council and the NIEA were “working together in relation to this site”.