Evidence about the health risks of high voltage power lines is growing day by day, an MSP has claimed.
SSE want to built a new 137-mile power line through Scotland
Labour backbencher Dr Richard Simpson compared growing evidence about the impact of power lines to the increase in evidence on passive smoking.
He made the case as members of a Holyrood committee considered a petition calling for regulations to deal with high voltage power lines.
The committee is meeting in response to plans for a new 137-mile power line.
Dr Simpson, an MSP for Mid Scotland and Fife, said when he had called for a ban on smoking back in 2001, the evidence on the dangers of second-hand cigarette smoke was "not all that great".
But he added: "Within a few years this parliament passed a ban on smoking.
"The situation with transmission lines is almost identical, in that the evidence is growing literally day by day."
Dr Simpson said that an inquiry by a cross-party group of MPs had stated children living within 200 metres of such power lines were at increased risk of leukaemia.
And he claimed there was increasing evidence that there was also a link to Alzheimer's disease.
SNP MSP Keith Brown said the cross-party inquiry at Westminster had recommended not building near to power lines, and added that other countries already adopted a precautionary approach to the issue.
Dr Simpson and Mr Brown spoke out at Holyrood's Public Petitions Committee, where colleagues were considering a petition calling on MSPs to urge ministers to acknowledge the potential health hazards associations with long-term exposure to electromagnetic fields from high voltage power lines.
The petition, from the campaign group Stirling Before Pylons, is also demanding planning regulations be brought in as a matter of urgency.
Committee member Nigel Don said the Scottish Government had to look beyond the existing evidence on the issue.
He said: "Research over a period of time builds up information from which eventually even the most blind can deduce what is totally obvious.
"The risk is governments and other organisations wait until the evidence is totally overwhelming.
"We should look at how evidence is building up."
The North East Scotland MSP added: "If you hang around long enough, enough evidence will be built up, by which time it may be too late.
"What we need to encourage the government to do is not look at the evidence we have at the moment, but to where it might lead and look over the horizon."
Committee convener Frank McAveety said the committee would send a "strong letter" to the Scottish Government on the issue.