Fears have been voiced that 'disaster' could strike if plans for much-needed affordable homes in north Norfolk are rejected.
Hastoe housing association wants to build nine new homes on an area of derelict land, infected by Japanese knotweed, at Beeston Regis.
It says it will spend £40,000 to clear the Cromer Road site of the invasive species if its plans are approved.
However, with members voting to defer their decision at a meeting of the local authority's development committee on Thursday, John Lefever, regional head of development for Hastoe, warned that, if left, the wild weed could spread to the neighbouring Beeston Common - a Site of Special Scientific Interest (SSSI).
He added: 'If that was to break out on the SSSI, I believe that would cause a (natural) disaster.'
Members agreed more information on the impact of the development was needed before they could approve the plans - including an archaeological and hydrological survey amid concerns it could have a detrimental impact on the neighbouring Beeston Regis priory, as well as an increased risk of flooding.
Speaking after the meeting, Mr Lefever said: 'We now have to outlay a lot of money but hopefully at the end of that we will get approval. The members seemed to be on the side of approval subject to all of this being agreeable.
'We had secured grant (funding) with the government that is time limited, so we will have to go back and negotiate that. But I understand where they are coming from, it is a contentious scheme.'
Local opinion remains divided on the scheme.
Councillor Peter Moore, chairman of the overview & scrutiny committee, said: 'It's quite clear that this isn't the right site for much needed affordable housing. It hurts me to (oppose) it, but some things are more important than nine houses.'
The medieval priory was dedicated to St Mary, and was an independent priory where the canons followed a lesser known Augustinian doctrine called the Peterstone Order - one of only two in the country to do so.
But Councillor Michael Knowles pointed out that the priory was built in 1206 to provide shelter and he added: 'That's what we're trying to do.'
Highlighting the shortage of affordable accommodation throughout north Norfolk, Councillor Richard Price, the council's portfolio holder for housing, said: 'It will still leave a huge gap but we need to provide more affordable homes.'
And Councillor Richard Shepherd, who stepped down from his position as chairman of the committee to express his own views, added: 'The kids need homes and this is a golden opportunity for building them.'
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